Socioeconomic disparity in cervical cancer screening among Korean women: 1998–2010

  • Minjee Lee1,

    Affiliated with

    • Eun-Cheol Park2,

      Affiliated with

      • Hoo-Sun Chang2,

        Affiliated with

        • Jeoung A Kwon1,

          Affiliated with

          • Ki Bong Yoo1 and

            Affiliated with

            • Tae Hyun Kim3Email author

              Affiliated with

              BMC Public Health201313:553

              DOI: 10.1186/1471-2458-13-553

              Received: 9 July 2012

              Accepted: 21 May 2013

              Published: 6 June 2013

              Abstract

              Background

              Cervical cancer is the sixth most common cause of cancer among Korean women and is one of the most preventable cancers in the world. This study aimed to investigate the change in cervical cancer screening rates, the level of socioeconomic disparities in cervical cancer screening participation, and whether there was a reduction in these disparities between 1998 and 2010.

              Methods

              Using the Korean Health and Nutrition Examination Survey, women 30 years or older without a history of cervical cancer and who completed a health questionnaire, physical examination, and nutritional survey were included (n = 17,105). Information about participation in cervical cancer screening was collected using a self-administered questionnaire. Multiple logistic regression analysis was performed to investigate the relationship between cervical cancer screening participation and the socioeconomic status of the women.

              Results

              The cervical cancer screening rate increased from 40.5% in 1998 to 52.5% in 2010. Socioeconomic disparities influenced participation, and women with lower educational levels and lower household income were less likely to be screened. Compared with the lowest educational level, the adjusted odds ratios (ORs) for screening in women with the highest educational level were 1.56 (95% confidence interval (CI): 1.05–2.30) in 1998, and 1.44 (95% CI: 1.12–1.87) in 2010. Compared with women with the lowest household income level, the adjusted ORs for screening in women with the highest household income level were 1.80 (95% CI: 1.22–2.68), 2.82 (95% CI: 2.01–3.96), and 1.45 (95% CI: 1.08–1.94) in 2001, 2005, and 2010, respectively.

              Conclusion

              Although population-wide progress has been made in participation in cervical cancer screening over the 12-year period, socioeconomic status remained an important factor in reducing compliance with cancer screening.

              Keywords

              Cervical cancer Screening Socioeconomic status Disparity

              Background

              Cervical cancer is one of the most preventable cancers in the world but it is the eighth leading cause of cancer-related deaths in Korea [1, 2]. Regular Papanicolaou (Pap) tests are an excellent diagnostic tool for detecting not only cancerous, but also precancerous cells, both of which can be removed [35]. Previous observational studies have consistently shown dramatic reductions in the cervical cancer mortality rate after the implementation of population-based screening programs [6, 7].

              Since its introduction in the 1940s, the Pap smear has been associated with sharp declines in cervical cancer incidence and mortality [8, 9]. In Korea, the age-adjusted incidence of cervical cancer dropped from 18.6 (per 100,000) in 1999 to 12.0 in 2009, and its mortality declined from6.2 per 100,000 in 1995 to 3.8 per 100,000 in 2009 [1, 10].

              In Korea, there are currently three main cancer screening programs [10], namely the National Cancer Screening Program (NCSP), the Korea National Health Insurance (NHI) program, and screening services voluntarily provided by independent medical facilities. In 1999, the Korean government created the NCSP and established a 10-year plan for cancer control [11]. The NCSP provided free cancer screening services for stomach, breast, and cervical cancers to medical aid recipients between 1999 and 2001 [12]. In 2002, coverage of free cancer screening was expanded to NHI beneficiaries within the lowest 20% income bracket, and in 2003, those within the lowest 30% income bracket were included in the target population. From 2005, the NCSP expanded coverage of free screening for stomach, breast, cervical, liver and colorectal cancer to Medical Aid recipients, and the NHI included beneficiaries who were within the lower 50% of income earners [13].

              Despite these public health efforts, the rate of cervical cancer screening may not be uniform across groups with different socioeconomic status. Previous studies suggested that socioeconomic disparities existed in cancer screening rates [14, 15], and, in particular, global evidence suggested that the cervical cancer screening rate was influenced by socioeconomic factors as well as demographic factors such as race [1621]. Studies in the United States and Korea also showed that socioeconomic disparities continued in cervical cancer screening participation, though there has been an improvement in overall screening rate [14, 22].

              Although the above-mentioned studies are informative in identifying important factors influencing cervical cancer screening, they are either cross-sectional studies or not nationally representative, or their study periods were in the late 1990s or the early 2000s. To achieve timely and challenging objectives in public health, such as improvement in cancer screening rates with a reduction in socioeconomic disparities, it is necessary to monitor the long-term trend. Therefore, the objective of this study was to investigate the changes in cervical cancer screening rate over the 12-year period from 1998 to 2010 in a nationally representative sample of Korean women, and to examine whether socioeconomic disparities in cervical cancer screening rates have been reduced over this period.

              Methods

              Data source and subjects

              This study used data from the 1998–2010 Korea National Health and Nutrition Examination Survey (KNHANES). The KNHANES is a nationally-representative study managed by the Korean Ministry of Health and Welfare. Participants were enrolled from the household registry using a stratified multistage probability design. The KNHANES consists of four parts: a health interview survey, a health behavior survey, a physical examination, and a nutritional survey. Trained interviewers conducted all surveys and trained healthcare professionals conducted all physical examinations. All participants provided informed consent before participation in the KNHANES.

              There were 211,116 women aged 30 years or older who completely answered the health behavior survey between 1998 and 2010. Women who did not provide information about cervical cancer screening or nutrition or who did not have an additional physical examination were excluded from the study. Finally, a total of 17,105 women (2,725 in 1998, 1,622 in 2001, 2,596 in 2005, 2,944 in 2008, and 2,737 in 2010) were included in the analysis.

              Independent variables and outcome variables

              From 1998 to 2001, participants were asked, “Have you ever been screened for cervical cancer?” and answers were recorded as either yes or no. From 2005 to 2010, participants were asked, “When was the last time you were screened for cervical cancer?” and answers were recorded as either never, less than 1 year ago, 1–2 years ago, or more than 2 years ago. According to the Korean NCSP guidelines, women 30 years of age and older should receive a Pap smear test every 2 years. In the present study, the outcome variable was whether participants adhered to the Korean NCSP guidelines. We defined participants as not adhering to the NCSP guidelines if they reported never being screened for cervical cancer or were examined more than 2 years prior to completing the questionnaire.

              Based on a literature review, we chose several variables as possible factors related to screening participation. Thus, our primary variables of interest were socioeconomic factors, including education, household income, and occupation. Other variables included in the study were age, marital status, health insurance type, health status (limitation in general activities and perceived health status), and health behavior (smoking and obesity). Educational status was divided into three groups: none or elementary school, middle school to high school, and university or higher. Household income, provided by the KNHANES, was calculated by dividing the monthly household income by the square root of the household size, and grouped into four household income quartiles. Occupation was categorized as “white collar (manager, professional level, office workers, service workers, sales)”, “blue collar (agriculture, fishery, technicians, mechanics, assemblers, simple labor)”, and “others (student, housewife, unemployed)”. Marital status was “married” vs. “not married”. Health insurance type was categorized as national health insurance for the self-employed, national health insurance for those not self-employed, and being in receipt of Medical Aid. Health status and health behavioral factors included limitation in general activities (yes, no), perceived health status (good or regular vs. bad), smoking (non, ex or current), and body mass index (BMI), categorized as < 18.5, 18.5– < 23, 23– < 25, and ≥ 25 kg/m2 according to the guidelines provided by the World Health Organization West Pacific Region (2000).

              Statistical analysis

              The KNHANES was based on a complex sample design. Therefore, all statistical analyses were performed using the survey procedure of SAS version 9.2 (SAS Inc., Cary, NC, USA), specifically designed to analyze such sample survey results. In the survey procedure, information pertaining to complex sample designs such as stratification, clustering, and unequal weighting is combined to analyze the parameters.

              We used descriptive statistics for the characteristics of the subjects, and reported the number and percentage for each variable. The participation rates in cervical screening were calculated according to all variables. The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure the strength of the association between the measured variables and screening participation. We regarded a p-value of less than 0.05 as statistically significant.

              Results

              Baseline characteristics and participation in cervical cancer screening

              The characteristics of the study population and participation rate in cervical cancer screening from 1998 to 2010 are summarized in Table 1. In this study, the majority of women were married, and enrolled in the NHI program. Most women reported no limitation in their daily activities and were non-smokers. The cervical cancer participation rates increased from 40.5% in 1998 to 52.5% in 2010.
              Table 1

              Basic characteristics of the study population and participation rate in cervical cancer screening in women ≥30 years, 1998–2010

              Variables

              1998

              2001

              2005

              2008

              2010

               

              Total

              %

              Screen

              %

              p-value

              Total

              %

              Screen

              %

              p-value

              Total

              %

              Screen

              %

              p-value

              Total

              %

              Screen

              %

              p-value

              Total

              %

              Screen

              %

              p-value

              Age (years)

                                       

              30-39

              715

              30.1

              362

              50.9

              <.0001

              369

              23.6

              191

              50.6

              <.0001

              710

              29.7

              362

              51.3

              <.0001

              707

              26.4

              363

              51.8

              <.0001

              617

              24.1

              317

              51.9

              <.0001

              40-49

              641

              24.9

              358

              55.9

               

              373

              23.8

              217

              58.8

               

              709

              27.7

              421

              59.0

               

              663

              28.1

              393

              60.2

               

              556

              26.6

              340

              61.1

               

              50-59

              557

              18.5

              219

              39.0

               

              310

              20.1

              132

              43.9

               

              469

              17.5

              217

              44.1

               

              562

              20.6

              312

              54.3

               

              623

              22.3

              385

              60.8

               

              60-69

              497

              15.6

              101

              21.6

               

              315

              18.3

              79

              26.3

               

              397

              13.1

              123

              34.2

               

              536

              13.4

              208

              40.7

               

              502

              13.6

              250

              49.1

               

              70+

              315

              11.0

              25

              6.4

               

              255

              14.1

              27

              9.1

               

              311

              11.9

              43

              14.7

               

              476

              11.5

              86

              17.9

               

              439

              13.4

              116

              26.3

               

              Education

                                       

              None or elementary school

              1,414

              45.5

              381

              26.1

              <.0001

              751

              44.3

              186

              25.4

              <.0001

              897

              32.1

              260

              29.9

              <.0001

              1,138

              29.9

              375

              35.5

              <.0001

              1,294

              43.8

              563

              43.6

              <.0001

              Middle or high school

              1,089

              44.6

              564

              52.0

               

              688

              44.2

              360

              53.1

               

              1,224

              48.8

              641

              52.1

               

              1,239

              48.6

              643

              51.9

               

              1,023

              40.9

              588

              59.4

               

              University or higher

              222

              10.0

              120

              54.4

               

              183

              11.6

              100

              53.4

               

              475

              19.1

              265

              55.2

               

              567

              21.5

              344

              62.6

               

              420

              15.3

              257

              59.5

               

              Marital status

                                       

              Married

              2,073

              77.2

              944

              46.8

              <.0001

              1,181

              73.0

              539

              45.8

              <.0001

              1,984

              76.0

              999

              50.6

              <.0001

              664

              18.6

              199

              32.0

              <.0001

              2,202

              81.3

              1,202

              55.2

              <.0001

              not married

              652

              22.8

              121

              19.1

               

              441

              27.0

              107

              27.6

               

              612

              24.0

              167

              29.6

               

              2,280

              81.4

              1,163

              53.2

               

              535

              18.7

              206

              40.8

               

              Household income

                                       

              Quartile 1

              770

              24.6

              184

              24.8

              <.0001

              509

              30.4

              109

              23.8

              <.0001

              666

              23.0

              187

              27.6

              <.0001

              694

              17.0

              220

              33.8

              <.0001

              635

              20.6

              252

              40.7

              <.0001

              Quartile 2

              643

              22.0

              247

              39.6

               

              407

              23.8

              175

              44.0

               

              624

              25.6

              255

              40.8

               

              756

              27.3

              328

              47.5

               

              685

              27.1

              336

              51.5

               

              Quartile 3

              708

              27.6

              345

              49.0

               

              347

              22.4

              170

              49.1

               

              669

              26.5

              343

              51.2

               

              759

              28.1

              382

              50.9

               

              710

              27.3

              391

              55.0

               

              Quartile 4

              604

              25.8

              289

              47.0

               

              359

              23.5

              192

              52.1

               

              637

              24.9

              381

              61.0

               

              735

              27.6

              432

              58.9

               

              707

              25.0

              429

              60.6

               

              Health insurance type

                                       

              NHI (self-employed)

              1,482

              53.7

              597

              41.3

              <.0001

              748

              46.2

              296

              40.0

              0.002

              1,066

              42.5

              451

              44.0

              0.064

              1,156

              39.9

              524

              48.4

              0.001

              932

              36.7

              446

              49.8

              0.252

              NHI (employee)

              1,120

              42.3

              453

              42.3

               

              780

              48.1

              333

              44.0

               

              1,412

              53.5

              671

              47.5

               

              1,662

              56.9

              805

              51.1

               

              1,712

              59.6

              919

              54.0

               

              Medical Aid

              123

              4.0

              15

              9.6

               

              94

              5.7

              17

              22.1

               

              118

              4.0

              44

              35.5

               

              126

              3.2

              33

              28.0

               

              93

              3.8

              43

              56.1

               

              Occupation

                                       

              white collar

              481

              20.3

              236

              48.9

              <.0001

              312

              19.4

              165

              50.5

              0.002

              663

              25.8

              352

              52.7

              0.003

              628

              23.9

              344

              54.0

              0.024

              670

              27.7

              369

              55.0

              0.233

              blue collar

              836

              23.8

              290

              35.4

               

              324

              20.1

              124

              40.9

               

              545

              18.8

              232

              43.6

               

              751

              21.4

              315

              45.3

               

              569

              21.4

              282

              54.0

               

              others

              1,408

              55.9

              539

              39.6

               

              986

              60.6

              357

              37.8

               

              1,388

              55.4

              582

              42.9

               

              1,562

              54.7

              700

              48.7

               

              1,498

              50.8

              757

              50.5

               

              Limitation in general activities

                                       

              Yes

              709

              27.4

              293

              44.5

              0.013

              201

              12.8

              62

              33.7

              0.045

              349

              12.5

              104

              30.8

              <.0001

              743

              21.4

              279

              44.1

              0.019

              929

              31.3

              433

              49.1

              0.024

              No

              2,016

              72.6

              772

              38.9

               

              1,421

              87.2

              584

              41.9

               

              2,247

              87.5

              1,062

              47.7

               

              2,201

              78.6

              1,083

              50.7

               

              1,808

              68.7

              975

              54.1

               

              Perceived health status

                                       

              Good or regular

              1,675

              63.9

              699

              43.0

              0.001

              1,014

              63.3

              456

              45.5

              <.0001

              1,807

              70.7

              891

              49.8

              <.0001

              1,993

              71.9

              956

              50.2

              0.165

              2,029

              74.8

              1,093

              54.1

              0.016

              Bad

              1,050

              36.1

              366

              36.0

               

              608

              36.7

              190

              32.9

               

              789

              29.3

              275

              35.3

               

              951

              28.1

              406

              46.8

               

              708

              25.2

              315

              47.8

               

              Smoking

                                       

              Non-smoker

              2,445

              89.7

              1,004

              42.2

              <.0001

              1,499

              92.1

              618

              42.4

              0.001

              2,375

              90.8

              1,101

              46.9

              0.000

              2,644

              88.7

              1,248

              49.9

              0.094

              2,503

              90.1

              1,299

              52.7

              0.026

              Ex-smoker

              72

              3.0

              15

              23.4

               

              24

              1.6

              4

              17.7

               

              104

              4.3

              38

              53.9

               

              148

              5.5

              61

              49.7

               

              133

              5.4

              72

              60.1

               

              Current smoker

              208

              7.2

              46

              25.4

               

              99

              6.2

              24

              25.0

               

              117

              4.9

              27

              28.4

               

              152

              5.8

              53

              38.8

               

              101

              4.5

              37

              40.7

               

              Body mass index (kg/m 2 )

                                       

              <18.5

              106

              3.8

              24

              26.8

              0.007

              65

              3.7

              21

              31.0

              0.165

              81

              3.0

              35

              42.2

              0.066

              123

              4.3

              50

              40.9

              0.030

              101

              3.7

              45

              45.5

              0.000

              18.5 ≤ 23

              1,076

              40.4

              437

              43.1

               

              601

              37.9

              257

              43.4

               

              4,050

              41.3

              493

              48.0

               

              1,209

              43.1

              580

              52.3

               

              1,150

              42.5

              624

              55.8

               

              23 ≤ 25

              637

              23.6

              262

              41.8

               

              399

              24.4

              160

              42.3

               

              637

              23.7

              292

              47.4

               

              683

              23.1

              320

              50.4

               

              640

              23.5

              358

              56.6

               

              25≤

              906

              32.2

              342

              37.7

               

              557

              33.9

              208

              38.2

               

              828

              31.9

              346

              41.3

               

              929

              29.5

              412

              45.2

               

              846

              30.3

              381

              45.6

               

              total

              2,725

              100.0

              1,065

              40.5

               

              1,622

              100.0

              646

              40.9

               

              2,596

              100.0

              1,166

              45.5

               

              2,944

              100.0

              1,362

              49.3

               

              2,737

              100.0

              1,408

              52.5

               

              NHI, National health insurance.

              Women with the lowest educational status had a participation rate of 26.1% in 1998 and 43.6% in 2010. However, women with the highest educational status reported a higher participation rate of 54.4% in 1998 and 59.5% in 2010. Women in the lowest household income group had a participation rate of 24.8% in 1998 and 40.7% in 2010. Women in the highest household income group had a participation rate of 47.0% in 1998 and 60.6% in 2010.

              Figure 1 indicates that the gaps between the highest and lowest educational status and income groups narrowed during the 12 years in Korea.
              http://static-content.springer.com/image/art%3A10.1186%2F1471-2458-13-553/MediaObjects/12889_2012_5478_Fig1_HTML.jpg
              Figure 1

              Cervical cancer screening rate by education and household income and occupation, 1998–2010.

              Factors associated with cervical cancer screening participation

              Table 2 shows the results of the multivariate logistic regression analysis for cancer screening. Of the socioeconomic factors considered, higher educational level was found to be associated with a higher OR in 1998, 2001, 2008, and 2010. Compared with the lowest educational level, the adjusted ORs of the highest education level were 1.56 (95% CI: 1.05–2.30), 1.90 (95% CI: 1.26–2.87), and 1.73 (95% CI: 1.12–2.66) in 1998, 2008, and 2010. A higher household income was also found to be associated with a higher OR in 2001, 2005, and 2010. Compared with the lowest household income level, the adjusted ORs of the highest household income level were 1.80 (95% CI: 1.22–2.68), 2.82 (95% CI: 2.01–3.96), and 1.45 (95% CI: 1.08–1.94) in 2001, 2005, and 2010, respectively.
              Table 2

              Factors associated with cervical cancer screening among women ≥30 years, 1998–2010

              Variables

              1998

              2001

              2005

              2008

              2010

              Education

                        

              None or elementary school

              1.00

               

              1.00

               

              1.00

               

              1.00

               

              1.00

               

              Middle or high school

              1.43

              (1.13-1.82)

              1.67

              (1.18-2.38)

              1.15

              (0.82-1.61)

              1.24

              (0.93-1.66)

              1.71

              (1.24-2.35)

              University or higher

              1.56

              (1.05-2.30)

              1.56

              (0.94-2.61)

              1.00

              (0.64-1.56)

              1.90

              (1.26-2.87)

              1.73

              (1.12-2.66)

              Household income

                        

              Quartile 1

              1.00

               

              1.00

               

              1.00

               

              1.00

               

              1.00

               

              Quartile 2

              1.22

              (0.92-1.62)

              1.65

              (1.16-2.34)

              1.39

              (1.00-1.93)

              1.09

              (0.82-1.46)

              1.12

              (0.84-1.49)

              Quartile 3

              1.52

              (1.11-2.07)

              1.72

              (1.15-2.59)

              1.93

              (1.44-2.59)

              1.05

              (0.78-1.40)

              1.21

              (0.89-1.66)

              Quartile 4

              1.31

              (0.95-1.81)

              1.80

              (1.22-2.68)

              2.82

              (2.01-3.96)

              1.34

              (0.97-1.84)

              1.45

              (1.08-1.94)

              Occupation

                        

              white collar

              1.00

               

              1.00

               

              1.00

               

              1.00

               

              1.00

               

              blue collar

              0.92

              (0.69-1.23)

              1.08

              (0.70-1.66)

              1.01

              (0.72-1.41)

              1.01

              (0.78-1.32)

              1.29

              (0.95-1.76)

              others

              1.12

              (0.87-1.44)

              1.02

              (0.79-1.35)

              1.04

              (0.79-1.35)

              1.18

              (0.93-1.49)

              1.20

              (0.92-1.57)

              Results are presented as adjusted odds ratios and (95% confidence intervals), and adjusted for age, marital status, health insurance type, limitation in general activities, perceived health status, smoking, and body mass index.

              Among the other variables, age was a statistically significant factor which was inversely related to cervical cancer screening during 1998–2010, suggesting that older women were less likely to participate in screening. Although marital status, health insurance type, and smoking status were statistically significant factors in one or two study years, their significance was either not as strong as socioeconomic status or somewhat inconsistent.

              Discussion

              The objective of this study was to examine the change in rates of participation in cervical cancer screening among Korean women from 1998 to 2010, and to test whether socioeconomic disparities in cervical cancer screening decreased, stayed the same, or worsened. We observed that the participation rate of Korean women 30 years or older in cervical cancer screening was 40.5% in 1998, 40.9% in 2001, 45.5% in 2005, 49.3% in 2008, and 52.5% in 2010. Although this suggests that there has been steady progress in improving the cervical cancer screening rate over the past decade, there is certainly room for improvement because the rate is still around 50%, significantly lower than in other economically developed countries. There were particularly low rates of participation in women with the lowest educational level (26.1% in 1998, 25.4% in 2001, 29.9% in 2005, 35.5% in 2008, and 43.6% in 2010), and in women with the lowest household income (24.8% in 1998, 23.8% in 2001, 27.6% in 2005, 33.8% in 2008, and 40.7% in 2010). Importantly, the participation rates of women in the lowest education and income groups markedly improved over the years, and the gaps with the highest education and income groups were reduced. The results of our study suggest important policy implications for policymakers to improve participation rates and to further reduce the difference in rates according to socioeconomic status.

              Previous studies have found educational level to be a significant predictor of cervical cancer screening participation [23, 24], and educational level has a huge effect on knowledge of the advantages of participation in cervical cancer screening after controlling for other covariates [25, 26]. The results of our study are consistent with previous studies in showing that educational level was significantly associated with participation in cervical cancer screening among Korean women, and, more importantly, that the association lasted over a decade. It is worth noting that two previous studies found that disparities in cancer screening by household income were improved, but there was no improvement for disparities in cancer screening by education level among Korean women [27, 28].

              Previous studies also found that household income was a significant predictor of cervical cancer screening participation [28, 29]. It was suggested that to improve cancer screening participation rates in lower income individuals, a primary health care intervention such as an organized program of cervical screening that focuses on deprived groups is needed [30]. Therefore, it is important to keep monitoring how public health policies impact on participation rates over time, such as that which expanded the scope of free cervical cancer examinations to women in the lower 50% income bracket of households [13].

              Our study has several limitations. First, although this study examined data in a 12-year study period, it was based on pooled cross-sectional data, from which we cannot detect a causal relationship. Second, the KNHANES is based on self-reported responses to participation in cervical cancer screening, which may raise acquiescence bias or recall bias. To minimize recall bias in collecting the data, the KNHANES was conducted by educated and trained interviewers. However, we acknowledge that the survey was unable to perform a cross-check with medical records. Therefore, recall and acquiescence (social desirability) bias can remain, and may result in misclassification. Although misclassification can be either random or nonrandom, we believe that, in a large nationwide survey such as KNHANES, it was random. Therefore, potential recall bias may lead to an association toward null, and an underestimate of the true association. A previous study also pointed out a similar possibility of underestimation of the actual participation rate [3133]. Finally, other factors that may be significant determinants of cervical cancer screening participation were not included in the current study. For example, there was no control for family history of cervical cancer, age at first sexual intercourse, and knowledge and attitudes about cervical cancer risk factors and benefits of the Pap test.

              Conclusion

              In conclusion, in the analysis of nationally representative data over a decade, we found that there was an increase in participation in cervical cancer screening programs by Korean women from 40.5% in 1998 to 52.5% in 2010, though the rate remained lower than in other developed countries. We also observed that despite the overall increase in screening rates, socioeconomic disparities continued to exist. Although screening rates in women with the lowest educational levels and household incomes improved over the period, they remained lower than in women of the highest education and income groups.

              These results demonstrate the need for more aggressive interventions and policies to improve participation in cervical cancer screening especially for those at a lower income and education level. Analyses of cervical cancer screening rates by measures of household income, educational level, and other factors over the long term may help policy-makers to better direct their resources to those of greatest need. Ensuring that free cervical cancer screening programs or other public health programs remain available for women in the lower income groups can lead us closer to national screening goals, yet policies or campaigns still need to address disparities in cervical cancer screening according to educational level.

              Declarations

              Acknowledgments

              This study was funded by a grant from the Korean Foundation for Cancer Research (7-2011-0489).

              Authors’ Affiliations

              (1)
              Department of Public Health, Institute of Health Services Research, Yonsei University
              (2)
              Department of Preventive Medicine and Public Health, Institute of Health Services Research, College of Medicine, Yonsei University
              (3)
              Graduate School of Public Health, Institute of Health Services Research, College of Medicine, Yonsei University

              References

              1. Korea Ministry of Health & Welfare, Center NC: Cancer facts & figures 2010 in the Republic of Korea. Seoul (Korea): Ministry of Health & Welfare; 2010.
              2. Whynes DK, Philips Z, Avis M: Why do women participate in the English cervical cancer screening programme? J Health Econ 2007,26(2): 306–325.PubMedView Article
              3. Abdullah F, Su TT: Enhancement of the cervical cancer screening program in Malaysia: a qualitative study. Asian Pac J Cancer Prev 2010,11(5): 1359–1366.PubMed
              4. Lee J, Seow A, Ling SL, Peng LH: Improving adherence to regular pap smear screening among Asian women: a population-based study in Singapore. Health Educ Behav 2002,29(2): 207–218.PubMedView Article
              5. Ibekwe CM, Hoque ME, Ntuli-Ngcobo B: Perceived benefits of cervical cancer screening among women attending Mahalapye District Hospital, Botswana. Asian Pac J Cancer Prev 2010,11(4): 1021–1027.PubMed
              6. Greenlee RT, Murray T, Bolden S, Wingo PA: Cancer statistics, 2000. CA Cancer J Clin 2000,50(1): 7–33.PubMedView Article
              7. Taylor R, Morrell S, Mamoon H, Wain G, Ross J: Decline in cervical cancer incidence and mortality in New South Wales in relation to control activities (Australia). Cancer Causes Control 2006,17(3): 299–306.PubMedView Article
              8. Paley PJ: Screening for the major malignancies affecting women: current guidelines. Am J Obstet Gynecol 2001,184(5): 1021–1030.PubMedView Article
              9. Watkins MM, Gabali C, Winkleby M, Gaona E, Lebaron S: Barriers to cervical cancer screening in rural Mexico. Int J Gynecol Cancer 2002,12(5): 475–479.PubMedView Article
              10. National Cancer Information Center: National Cancer Control Program . [http://​www.​cancer.​go.​kr/​mbs/​cancer/​index.​jsp] []
              11. International Agency for Research on Cancer: Screening for cancer of the uterine cervix . Lyon: International Agency for Research on Cancer; 1986.
              12. Sung NY, Park EC, Shin HR, Choi KS: Participation rate and related socio-demographic factors in the national cancer screening program. J Prev Med Public Health 2005,38(1): 93–100.PubMed
              13. Kwak MS, Park EC, Bang JY, Sung NY, Lee JY, Choi KS: Factors associated with cancer screening participation, Korea. J Prev Med Public Health 2005,38(4): 473–481.PubMed
              14. Adams EK, Breen N, Joski PJ: Impact of the national breast and cervical cancer early detection program on mammography and Pap test utilization among white, hispanic, and african american women: 1996–2000. Cancer 2007,109(2 Suppl): 348–358.PubMedView Article
              15. Fukuda Y, Nakamura K, Takano T: Reduced likelihood of cancer screening among women in urban areas and with low socio-economic status: a multilevel analysis in Japan. Public Health 2005,119(10): 875–884.PubMedView Article
              16. Moser K, Patnick J, Beral V: Inequalities in reported use of breast and cervical screening in Great Britain: analysis of cross sectional survey data. BMJ 2009, 338:b2025-b2025.PubMedView Article
              17. Martin-Lopez R, Hernandez-Barrera V, de Andres AL, Carrasco-Garrido P, de Miguel AG, Jimenez-Garcia R: Trend in cervical cancer screening in Spain (2003–2009) and predictors of adherence. Eur J Cancer Prev 2012,21(1): 82–88.PubMedView Article
              18. Lee K, Lim HT, Hwang SS, Chae DW, Park SM: Socio-economic disparities in behavioural risk factors for cancer and use of cancer screening services in korean adults aged 30 years and older: the third korean national health and nutrition examination survey, 2005 (KNHANES III). Public Health 2010,124(12): 698–704.PubMedView Article
              19. Martinez-Huedo MA, Lopez de Andres A, Hernandez-Barrera V, Carrasco-Garrido P, Martinez Hernandez D, Jimenez-Garcia R: Adherence to breast and cervical cancer screening in spanish women with diabetes: associated factors and trend between 2006 and 2010. Diabetes Metab 2012,38(2): 142–148.PubMedView Article
              20. Park MJ, Park EC, Choi KS, Jun JK, Lee HY: Sociodemographic gradients in breast and cervical cancer screening in Korea: the korean national cancer screening survey (KNCSS) 2005–2009. BMC Cancer 2011, 11:257.PubMedView Article
              21. Wang JH, Sheppard VB, Schwartz MD, Liang W, Mandelblatt JS: Disparities in cervical cancer screening between asian american and Non-hispanic white women. Cancer Epidemiol Biomarkers Prev 2008,17(8): 1968–1973.PubMedView Article
              22. Jang SN, Cho SI, Hwang SS, Jung-Choi K, Im SY, Lee JA, Kim MK: Trend of socioeconomic inequality in participation in cervical cancer screening among Korean women. J Prev Med Public Health 2007,40(6): 505–511.PubMedView Article
              23. Nene B, Jayant K, Arrossi S, Shastri S, Budukh A, Hingmire S, Muwonge R, Malvi S, Dinshaw K, Sankaranarayanan R: Determinants of womens participation in cervical cancer screening trial, Maharashtra . India. Bull World Health Organ 2007,85(4): 264–272.View Article
              24. Shin JH, Kim DW, Cho SH, Moon H, Kim DS, Choi BY: The knowledge and attitude to the uterine cervix cancer and screening program in the patients with cervical cancer and recipients of pap smear . Korean J ObstetGynecol 1993,36(2): 215–225.
              25. Tsui J, Tanjasiri SP: Cervical cancer screening among Thai women in Northern California . J Womens Health (Larchmt) 2008,17(3): 393–401.View Article
              26. Taylor VM, Yasui Y, Burke N, Nguyen T, Acorda E, Thai H, Qu P, Jackson JC: Pap testing adherence among Vietnamese American women . Cancer Epidemiol Biomarkers Prev 2004,13(4): 613–619.PubMed
              27. Chun EJ, Jang SN, Cho SI, Cho Y, Moon OR: Disparities in participation in health examination by socio-economic position among adult Seoul residents . J Prev Med Public Health 2007,40(5): 345–350.PubMedView Article
              28. Kwak MS, Choi KS, Spring BJ, Park S, Park E-C: Predicting the stages of adoption of cervical cancer screening among Korean women . Prev Med 2009,49(1): 48–53.PubMedView Article
              29. Paskett ED, McLaughlin JM, Reiter PL, Lehman AM, Rhoda DA, Katz ML, Hade EM, Post DM, Ruffin MT: Psychosocial predictors of adherence to risk-appropriate cervical cancer screening guidelines: a cross sectional study of women in Ohio Appalachia participating in the community awareness resources and education (CARE) project . Prev Med 2010,50(1–2): 74–80.PubMedView Article
              30. Baker D, Middleton E: Cervical screening and health inequality in England in the 1990s . J Epidemiol Community Health 2003,57(6): 417–423.PubMedView Article
              31. Messina CR, Kabat GC, Lane DS: Perceptions of risk factors for breast cancer and attitudes toward mammography among women who are current, ex- and non-smokers . Women Health 2002,36(3): 65–82.PubMedView Article
              32. Clark MA, Rakowski W, Ehrich B: Breast and cervical cancer screening: associations with personal, spouse’s, and combined smoking status . Cancer Epidemiol Biomarkers Prev 2000,9(5): 513–516.PubMed
              33. McPhee SJ, Nguyen TT, Shema SJ, Nguyen B, Somkin C, Vo P, Pasick R: Validation of recall of breast and cervical cancer screening by women in an ethnically diverse population . Prev Med 2002,35(5): 463–473.PubMedView Article
              34. Pre-publication history

                1. The pre-publication history for this paper can be accessed here:http://​www.​biomedcentral.​com/​1471-2458/​13/​553/​prepub

              Copyright

              © Lee et al.; licensee BioMed Central Ltd. 2013

              This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://​creativecommons.​org/​licenses/​by/​2.​0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.