Open Access
Open Peer Review

This article has Open Peer Review reports available.

How does Open Peer Review work?

Self-reported cataracts in older adults in Ghana: sociodemographic and health related factors

  • Alfred E Yawson1, 2Email author,
  • Edith M Ackuaku-Dogbe3,
  • Nana A Hagan Seneadza1, 2,
  • George Mensah1,
  • Nadia Minicuci1, 4,
  • Nirmala Naidoo5,
  • Somnath Chatterji5,
  • Paul Kowal5, 6 and
  • Richard B Biritwum1
BMC Public Health201414:949

https://doi.org/10.1186/1471-2458-14-949

Received: 20 October 2013

Accepted: 9 September 2014

Published: 12 September 2014

Abstract

Background

Changes in function of sensory organs with increasing age have significant impact on health and wellbeing of older persons. This paper describes cataract, a chronic eye condition, self-reported among older adults in Ghana and the need for improving access to eye care services.

Methods

This work was based on the World Health Organization’s multi-country Study on global AGEing and adult health (SAGE), conducted in six countries including Ghana. SAGE Wave 1 in Ghana was conducted in 2007–2008 in a nationally representative sample of 4278 older adults, ≥ 50 years. Data were obtained on sociodemographic and health factors related to self-reported cataracts in older persons in Ghana. Data were analysed using descriptive measures (frequencies and proportions), chi-square test for associations in categorical outcome measures, and logistic regression for predictors of cataracts with SPSS version 21.

Results

Overall prevalence of self-reported cataracts among 4278 older adults in Ghana was 5.4%. Prevalence was proportionately higher for women (5.9%) than men (4.7%). Reported cataracts increased with age, among urban residents, in older adults living without partners and among those with the worse life satisfaction index. Older adults in lower income groups, poorly educated or living alone had difficulty seeking vision care services. Prevalence was 8.4% among persons with diabetes, 10.4% among hypertensives and 11.4% in persons with previous history of stroke. Among older persons who had ever used alcohol or tobacco, prevalence rates of reported cataracts were 5.7% and 4.9%, respectively. Logistic regression analysis indicated that increasing age, lower income status and self-reported hypertension were significantly associated with cataract among older adults in Ghana.

Conclusions

Cataract is prevalent in older people in Ghana with approximately 1 in 20 people aged 50 years or older reporting a previous diagnosis of cataract. As cataract surgery is restorative, a public health approach on behavioural modification, well structured national outreach eye care services (for rural residents), inclusion of basic eye health services at sub-district levels, increased family support and national health insurance for older persons is indicated.

Keywords

Older adult Cataracts Eye care service Subjective wellbeing Ghana Low income countries

Background

Cataract is the leading cause of blindness accounting for nearly 48% of blindness globally [1, 2]. It poses a substantial economic and public health burden especially in developing countries. According to a World Health Organization (WHO) report on global blindness, approximately 90% of global cataract is seen in developing countries and estimates that more than 82% of all blindness occurs in individuals aged 50 and older [2].

In a population based study in Ghana, the prevalence rates of cataract causing low vision or blindness in people aged 40 years and above was 9% in the Volta region [3] and 2% in people aged 30 years and above in the Wenchi area of the Brong Ahafo region [4], two of the ten regions in Ghana. The burden of cataracts is not limited to financial costs to society alone, older persons living with un-operated cataracts are likely to have significantly reduced quality of life due to low vision. Other co-morbid conditions in older persons further reduces their quality of life. Decreases in functional abilities may be attributed to other age-related processes but may actually be associated with the onset of cataract.

Some health, lifestyle and environmental conditions have been associated with the development of cataracts. Research has strongly associated diabetes, smoking and ultra violet light exposure with the development of age related cataract [59]. Other factors inconclusively implicated in the development of cataracts include body mass index [10, 11] and post menopausal decline in estrogen [12].

Aging is often accompanied by the cumulative impact of chronic disease, increased prevalence of disability, worsening health status and reduced quality of life among the growing number of older persons. Aging, in itself, has been associated with a decline in visual functioning, with associated decline in physical and mental functioning. A number of studies have demonstrated impact of cataract related visual impairment on quality of life [13, 14]. These studies, showed that worsening of general functioning, psychosocial and overall eyesight were associated with increased visual loss. Those with increased visual loss were more likely to report dissatisfaction with quality of life and had poorer self-rated health than persons with normal vision.

In addition, smoking, body-mass index, and exercise patterns in midlife and late adulthood have been suggested as predictors of disability in later years. For the average person, efforts to reduce modifiable health risks may result in a postponement of initial disability and decreased lifetime disability [15].

Current eye health services in Ghana are organized at three levels, national, regional and district [16]. The national and regional levels provide specialized eye care services through the teaching and regional hospitals. Basic eye health services at the district is provided through district hospitals by ophthalmic nurses (i.e. state registered general nurses who have additional training in ophthalmology). Unlike the general health delivery system with structures to provide health care at sub-district and community level [16], eye health services is limited to the district level. Sub-districts and communities (where most of the rural population reside) receive eye care services through outreach programmes and special mobile eye clinics.

The goal of this analysis is to describe the sociodemographic, health related factors and life satisfaction index in older adults with self-reported cataract in Ghana. It is aimed at providing guidance for national plans on eye care for older persons and to contribute to national policy on interventions to mitigate health related factors in the older adult population.

Methods

SAGE Wave 1 was undertaken in Ghana in a partnership between the University of Ghana’s Department of Community Health, the Ministry of Health and WHO, as part of a multi-country longitudinal study to complement existing aging data sources and to inform policy and programmes [17, 18]. A nationally representative sample of respondents ≥ 50 years were interviewed on socio-demographic background, health risk factors, chronic conditions, well-being and health insurance coverage. Face-to-face interviews and data entry were undertaken between May 2007 and June 2008. Ethical approval for SAGE Wave 1 in Ghana was given by WHO’s Ethical Review Board and the University of Ghana Medical School Ethics and Protocol Review Committee. All study participants provided informed consent [17, 18].

Measures

Demographic and socioeconomic variables included sex, age, marital status, highest educational level completed, health insurance status and household income levels. Access to health care in Ghana is through the National Health Insurance Scheme (NHIS), introduced in 2003 and operationalized in most public and private health facilities in 2005. Basic eye care services including cataract surgery is covered by the NHIS. Assessment of health insurance status of older persons was based on this[19]. Educational level was categorized as low (primary or basic school completed or less) and high (at least secondary school completed or higher).

Chronic diseases

SAGE collected data on prevalent chronic diseases in older persons in Ghana. Data on four of these chronic conditions (cataract, diabetes mellitus, hypertension and stroke) were used in this analysis. For cataract, the question asked was: “ In the last 5 years, were you diagnosed with a cataract in one or both of your eyes (a cloudiness in the lens of the eye) by a health care professional?” Diagnosis of cataract in Ghana is done by a doctor or nurse trained in ophthalmology. SAGE Wave 1 in Ghana included operated and unoperated cataract within the self-reported diagnosis of cataract in the last 5 years.

The prevalence rates for the other chronic diseases were obtained through responses to the question “Has a health care professional ever told you, you have…?". Though SAGE Wave 1 measured blood pressure, the analysis considered only self-reported hypertension due to the focus on self-reported ill-health among older persons in Ghana [17, 18].

Tobacco use

Lifetime tobacco use was assessed with the question ‘Have you ever smoked tobacco or used smokeless tobacco?’ SAGE considered tobacco products such as cigarettes, cigars, pipes, chewing tobacco, or snuff. Details on how tobacco use was assessed is provided in published elsewhere [17, 18, 20].

Alcohol use

Lifetime alcohol use was assessed from responses to the question ‘Have you ever consumed a drink that contains alcohol (such as beer, wine, spirits, etc.)?’ SAGE Wave 1 quantified alcohol (commercially available and home-brewed beverages) in "standard drink" units as recommended by the World Health Organization [17, 18, 20].

Body mass index (BMI)

Was obtained from measured weight and height of respondents.

Subjective wellbeing (SWB)

Well-being or life satisfaction was assessed through a multi-dimensional scale, the WHO Disability Assessment Schedule 2.0, including a question about satisfaction with life overall [17, 18]. SWB as a single item measure was based on the overall life satisfaction question. As in a similar analysis by Yawson et al., 2013, the responses to this question were categorized into satisfied (very satisfied and satisfied), indifferent (neither satisfied nor dissatisfied) and not satisfied (dissatisfied and very dissatisfied) [21].

Wealth or income quintiles

Were derived from the household ownership of durable goods, dwelling characteristics and access to services (improved water, sanitation and cooking fuel) for a total of 21 assets. Wealth levels were generated through a multi-step process, where asset ownership was converted to an asset ladder, Bayesian post-estimation method used to generate raw continuous income estimates, and then income transformed into quintiles [17, 18, 20].

Data analysis

Demographic and socio-economic variables such as age, location (urban/ rural), educational level, marital status (due to its relevance in social support and health access), and income levels were described using proportions. Chi-square tests of significance were used to compare distribution of cataract and demographic, socioeconomic, health risk and life satisfaction indices.

Binary logistic regression analysis was done to determine factors associated with cataract in the older persons. Ever been diagnosed with cataract was the binary dependent variable in the regression model. Independent variables used included age, sex, location (urban/rural), educational level, marital status, income quintile, health insurance status, self-reported chronic conditions (diabetes, hypertension and stroke), alcohol use, tobacco use, and subjective wellbeing. Decisions were based on adjusted odds ratio [AOR] and p-values at 95% confidence level. Data were analysed using SPSS version 21.

Results

Overall prevalence of cataracts in the 4278 older adults in Ghana was 5.4%. Prevalence was proportionately higher in women (5.9%) than men (4.7%); though this difference was not statistically significant (p-value = 0.067). The prevalence of cataract clearly showed an age gradient: higher values were reported in the older age groups (from 2.1% in 50–59 age group to 9.5% in ≥ 70 years). Age differences in prevalence of cataract was statistically significant (p-value = 0.001). Urban residents reported statistically significant higher rates (6.6%) than rural residents (4.4%). Older adults living without a partner (separated/divorced/ widowed) reported significantly higher prevalence of cataract (6.6%), compared to those living with a partner (married/cohabiting) (4.3%) as shown in Table 1. Older adults with secondary school education or higher, had a higher prevalence compared to those with primary school completed or less. Older adults in high income groups (Q4 and Q5) reported significantly higher levels of cataract (6.6%) compared to those within low income group (Q1 and Q2) (4.3%). Interestingly, older adults on national health insurance reported significantly higher prevalence of cataract (7.1%) than those without insurance (4.2%).
Table 1

Prevalence of self-reported cataracts in older adults in Ghana by demographic and socioeconomic characteristics, SAGE Wave 1

Characteristics

Self reported cataract

X2(p-value)

n (%)

N

Sex

   

Male

106 (4.7)

2249

3.35 (0.067)

Female

120 (5.9)

2029

 

Age group

   

50–59

35 (2.1)

1681

 

60–69

59 (4.9)

1196

83.88 (0.001)

70+

133 (9.5)

1401

 

Residence

   

Urban

115 (6.6)

1749

9.46 (0.002)

Rural

111 (4.4)

2529

 

Marital status

   

Never married

4 (8)

54

 

Living with partner (married/cohabiting)

104 (4.3)

2426

11.92 (0.003)

Living without partner (Separated/divorced/Widowed)

119 (6.6)

1798

 

Highest educational level

   

Primary school completed or less

162 (5.2)

3114

0.229 (0.632)

Secondary school and above

66 (5.7)

1164

 

Income quintile

   

Q1 and Q2 (low)

105 (4.3)

2441

 

Q3 (middle)

2 (5.7)

39

10.71 (0.005)

Q4 and Q5 (high)

119 (6.6)

1798

 

Health insurance

   

Yes

116 (7.1)

1638

16.58 (0.001)

No

111 (4.2)

2640

 

Total respondents

231 (5.4)

4278

 
As demonstrated in Table 2, prevalence of cataract among obese older adults was 5.8%. Among older adults with self-reported chronic non-communicable conditions, prevalence was 8.4% among those with diabetes, 10.4% among hypertensives and 11.4% in those with previous history of stroke. The prevalence of cataract among older adults who had ever used alcohol was 5.7%. Interestingly, older persons who had used tobacco had a lower prevalence of self-reported cataract (4.9%) compared to those who had never used tobacco.
Table 2

Prevalence of self-reported cataracts in older adults in Ghana by health related factors and subjective wellbeing, SAGE Wave 1

Characteristics

Self reported cataract

X2(p-value)

n (%)

N

Obese

   

Yes

26 (5.8)

449

0.42 (0.519)

No

195 (5.1)

3829

 

Self-reported diabetes

   

Yes

14 (8.4)

162

3.31 (0.069)

No

214 (5.2)

4116

 

Self-reported hypertension

   

Yes

60 (10.4)

580

35.63 (0.001)

No

166 (4.5)

3698

 

Self-reported stroke

   

Yes

12 (11.4)

108

8.74 (0.003)

No

213 (5.1)

4170

 

Alcohol use

   

Ever

143 (5.7)

2512

0.001 (0.976)

Never

93 (5.3)

1766

 

Tobacco use

   

Ever

54 (4.9)

1111

0.395 (0.530)

Never

171 (5.4)

3167

 

Level of subjective well being/life satisfaction

Satisfied

113 (4.7)

2407

 

Indifferent

105 (5.8)

1799

5.76 (0.056)

Not satisfied

7 (9.9)

72

 

Analysis of satisfaction with daily living among older adults found the highest prevalence of cataract among those who expressed dissatisfaction with life (9.9%) and the lowest prevalence (4.7%) among those satisfied with life.

Important associated factors of cataract in older adults in Ghana

Logistic regression analysis indicated that increasing age, income status and self-reported hypertension were factors significantly associated with cataract among older adults in Ghana as in Table 3. With increasing age, the risk of cataract was highest in 60–69 years (AOR = 7.8, CI 4.424-13.684 ), and slightly higher in the ≥ 70 years (AOR = 2.5, CI 1.551- 4.125) compared to older adults 50–59 years. High income (Q4 and Q5) was shown to be associated with a lower risk for self-reported cataract (AOR = 0.6, CI 0.415-0.983 ) compared to the low income group (Q1 and Q2). Older adults who did not self-report hypertension had lower risk for self-reported cataract (AOR = 0.4, CI 0.248-0.625).
Table 3

Factors associated with self-reported cataract in older adults in Ghana, SAGE Wave 1

Characteristic

Odds ratio

 

95% Confidence interval

P-value

Lower

Upper

Sex

    

Male

---

   

Female

1.364

0.77

2.42

0.287

Location

    

Urban

---

   

Rural

.926

0.59

1.44

0.733

Age group

    

50-59 years

---

   

60-69 years

7.781

4.42

13.68

0.001

70 years and above

2.530

1.55

4.13

0.001

Educational level

    

Primary completed or less

---

   

Secondary or higher

1.371

0.88

2.14

0.164

Marital status

    

Never married

---

   

Living with partner (currently married

    

and cohabiting)

0.190

0.02

1.76

0.143

Living without partner (separated/divorced and widowed)

0.467

0.10

2.19

0.334

Income status

    

Low income level (Q1 and Q2)

---

   

Middle income level (Q3)

2.502

0.55

11.41

0.236

Higher income level (Q4 and Q5)

0.639

0.42

0.98

0.042

Self-reported Stroke

    

No

---

   

Yes

1.124

0.38

2.00

0.754

Self-reported Diabetes

    

Yes

---

   

No

1.169

0.52

2.61

0.703

Self-reported hypertension

    

Yes

---

   

No

0.394

0.25

0.63

0.001

Lifetime Tobacco use

    

Ever

---

   

Never

1.187

0.68

2.06

0.543

Lifetime alcohol

    

Ever

    

Never

0.879

0.55

1.40

0.587

Level of subjective well being/life satisfaction

Satisfied

---

   

Indifferent

.381

.046

3.14

0.370

Dissatisfied

.328

.040

2.70

0.299

Discussion

Cataract is one of the major conditions chosen by the global initiative, Vision 2020—The Right to Sight, due to the magnitude of its contribution to the burden of blindness [22]. Several studies which focused on the burden of visual loss from cataracts demonstrate the prevalence of cataracts increases with increasing age and is slightly higher among women [2325]. Our study confirms the findings from these studies.

An appreciation of the impact of visual impairment or blindness on one’s functional ability and quality of life is useful in providing a comprehensive picture of the burden of visual impairment beyond clinical evaluation [26]. In addition, other non-communicable and chronic diseases currently accounting for 60% of deaths globally per annum and 47% of the global burden of disease [27] are mostly associated with aging. The frequency of these conditions increases with age, and they do occur concurrently with cataract as shown in this and other studies [28, 29].

Prevalence of cataract among older persons was determined through a question on whether they have been told by a health professional that they have cataract. In the health delivery system of Ghana, these health professional are either doctors or ophthalmic nurses with capacity to diagnose basic eye conditions including cataracts [16]. The observation suggests that those diagnosed might have accessed eye care services at health facilities or during screening programs. Thus increased prevalence may imply improved access to health care and not necessarily increased disease burden. The prevalence of cataract in this group of people (5.4%) is lower than that reported in the cataract prevalence study among those 40 years and older in the Volta region, one of the ten regions in Ghana (9%) [3]. These differences may be as a result of the differences in the study design, the earlier studies were based on population screening and limited to cataract causing low vision or blindness. In this analysis most cases of cataracts (of any degree of maturity), were more likely to have been diagnosed by trained health professionals at the health facility; hence the relatively higher prevalence in the earlier studies.

Urban residents reported statistically significant higher rates (6.6%) than rural residents (4.4%). This may be related to better access to eye health care with aggregation of eye care services in urban areas in Ghana. Rural areas have limited access and residents depend mainly on erratic outreach services for eye health care. Most rural residents access health care at sub-district levels (health centres and community-based health care) where routine eye care services are unavailable. In addition overall cataract surgical uptake among older persons in Ghana from the national report on SAGE wave 1 was 48.9% [17]. Access to eye care services is critical for early risk detection and prevention of blindness or visual impairment. Well structured outreach eye care services for rural residents or inclusion of basic eye health services at sub-district levels is critical to improve eye health of older persons in Ghana.

Older adults living without a partner (separated/divorced/ widowed) reported significant higher prevalence of cataract (6.6%), compared to those with a partner (married/cohabiting) (4.3%). It may imply this group of older persons might have assessed health care previously and been diagnosed or that older persons living alone are less likely to access health care services; thus the relative higher prevalence of cataract. This may be related to other social support factors; the older adult with visual disability may have multiple disabilities as well [29]. These older adult would need more assistance (physical, social and economic) to access eye care services and living alone may limit the availability of this assistance.

Persons with higher education, higher income and health insurance reported significant higher prevalence of cataract. A potential explanation is their ability to access eye care services due to better knowledge on availability of these services, ability to afford other personal costs involved in seeking health care and improved financial access to health care through the national health insurance scheme. Older adults with low educational background on the other hand may not attach much importance to seeking early and appropriate eye care services. The fifth round of the Ghana living standards survey report in 2008 showed that 31% of all adults had never been to school, less than one-fifth (17%) attended school but did not obtain any qualifications; while a small percentage of 14% possessed secondary or higher qualification [30]. Improving the literacy level of Ghanaians is likely to encourage self-reporting to medical facilities for early diagnosis and treatment.

Generally, in this analysis, older persons in low income groups, poorly educated or living alone had some difficulty seeking vision services and care to prevent blindness or visual impairment. This constitute a vulnerable group who may require special attention to access eye care services. Social protection strategies including enrolment of older adults freely on the national health insurance scheme (NHIS) should be a national health policy worth considering. Currently only older persons ≥ 70 years are eligible for free enrolment on the NHIS [31].

Analysis also demonstrated that prevalence of self-reported cataract was relatively higher in older persons with health related factors such as obesity, diabetes, hypertension, previous history of stroke and alcohol use. Prevalence of cataract in persons with obesity, diabetes, hypertension, previous history of stroke were 5.1%, 8.4%, 10.4% and 11.4% respectively. Among older persons who had ever used alcohol or tobacco, the prevalence was 5.7% and 4.9% respectively. These findings agree with those in other studies that found similar associations [23, 24]. An interesting observation however, was that older persons who had used tobacco had relatively lower prevalence of self-reported cataract. The authors suggest a more detailed study to determine possible factors that may account for this.

A public health approach on behavioural modification (for modifiable and preventable risks- obesity, alcohol consumption and tobacco use) may be required to improve the eye health of older persons in Ghana. Diabetes is recognized as a significant risk factor due to it metabolic effect on the crystalline lens [32, 33]; disease specific health prevention efforts at national and local levels is imperative.

Analysis on satisfaction with daily living among older persons indicate prevalence of cataract is highest among the few older persons who expressed dissatisfaction with life (9.9%) and is lowest (4.7%) among those satisfied with life. Studies among older persons in communities, identified hearing and visual impairments as important factors that lead to functional decline and increased morbidity (imbalance, hip fracture, and depression) as well as mortality [29]. In addition, visual loss in older adults poses significant challenges for families who have to support them; existence of such social support for older persons in communities is often lacking [29].

In Bangladesh, Polack and others in 2008 [27] found that cataract related visual impairment negatively affected perceived health and well-being, beyond vision-specific experience. Also worsening general functioning, psychosocial and overall eyesight scores were found to be associated with increased visual loss. In their study, those with self-reported cataract significantly reported more problems with mobility, self-care, activities of daily living, pain and depression/anxiety and had significantly poorer mean self-rated health. Influence of cataract on the health and social wellbeing of individuals have also been demonstrated in studies from Kenya [14] and India [13].

Limitation

Calling other binding diseases as cataract, and labelling any ocular/orbital/adnexal surgical procedures as cataract surgery by the older adults are very likely. The SAGE Wave 1 relied on individual submissions and did not objectively confirm cataract diagnosis or cataract surgery. The self-report of health conditions, (such as cataract and hypertension), is likely to result in underestimation of prevalence rates compared to measured rates [34]. The analysis however, provides information on prevalence of self-reported cataract among older persons across the regions of Ghana as a baseline for further investigations.

Conclusion

Prevalence of cataract increased significantly with increasing age, was slightly higher among women, urban residents and older adults living without a partner. Significantly higher prevalence of self-reported cataract were observed in older persons with higher education, higher income and health insurance (due probably to better access to eye health care). Those who were poorly educated and with low incomes had some difficulty seeking vision services and care to prevent blindness or visual impairment.

Risk modification through effective primary prevention and health promotion efforts; behavioural modification, including public health campaigns are key efforts to limit the burden of cataract among older persons in Ghana. Well structured national outreach eye care services for rural residents and inclusion of basic eye health services at sub-district health levels of Ghana's primary health care structure are needed. Increased family support and national social protection strategies (including enrolment of older adults on national health insurance scheme) linked to the national aging policy will improve access to eye health care.

Authors’ information

Yawson AE , Mensah G, MinicuciN and Biritwum RB are members of the WHO Multi-country SAGE Team who conducted the SAGE Survey in Ghana. Naidoo N, Chatterji S and Kowal P are members of the WHO Multi-country SAGE Team and coordinators of the multi-country study at the WHO Headquarters in Geneva. EM Ackuaku-Dogbe is a Consultant Ophthalmologist of the University of Ghana Medical School and NA Hagan Seneadza is a Specialist Public Health Physician of the Korle-Bu Teaching Hospital.

Declarations

Acknowledgement

We are grateful to all respondents and interviewers who made the SAGE survey in Ghana possible. Financial support was provided by the US National Institute on Aging through Interagency Agreements (OGHA 04034785; YA1323-08-CN-0020; Y1-AG-1005-01) with the World Health Organization and a Research Project Grant (R01 AG034479- 64401A1). WHO contributed financial and human resources to SAGE. The Ministry of Health, Ghana, is supportive of SAGE.

The Department of Community Health of University of Ghana Medical School contributed training facilities, data entry support, and storage of materials. The Ghana Statistical Office provided the sampling information for the sampling frame and updates.

Authors’ Affiliations

(1)
Department of Community Health, University of Ghana Medical School, College of Health Sciences
(2)
Public Health Unit, Korle-Bu Teaching Hospital
(3)
Department of Surgery, Eye Unit, University of Ghana Medical School, College of Health Sciences
(4)
Institute of Neuroscience, National Council Research
(5)
Multi-Country Studies unit, World Health Organization
(6)
University of Newcastle Research Centre on Gender, Health and Aging

References

  1. World Health Organization: Global Data on Visual Impairments 2010. 2012, Geneva, Switzerland: Published by the World Health Organization, WHO/NMH/PBD/12.01 (http://www.who.int/about/regions/en/index.html)Google Scholar
  2. Resnikoff S, Pascolini D, Etya’ale D: Global data on visual impairment in the year 2002. Bull World Health Organ. 2004, 82: 844-851.PubMedPubMed CentralGoogle Scholar
  3. Guzek JP, Anyomi FK, Fiadoyor S, Nyonator F: Prevalence of blindness in people over 40 years in the volta region of Ghana. Ghana Med J. 2005, 39 (2): 52-62.Google Scholar
  4. Moll AC, Van der Linder AJH, Hogeweg M, Schader WE, Hermans J, De K: Prevalence of blindness and low vision of people over 30 years in the Wenchi district, Ghana, in relation to eye care programmes. BJO. 1994, 78: 275-279. 10.1136/bjo.78.4.275.View ArticleGoogle Scholar
  5. West SK, Valmadrid CT: Epidemiology of risk factors for age-related cataract. Surv Ophthalmol. 1995, 39: 323-324. 10.1016/S0039-6257(05)80110-9.View ArticlePubMedGoogle Scholar
  6. McCarty CA, Taylor HR: A review of the epidemiologic evidence linking ultraviolet radiation and cataracts. Dev Ophthalmol. 2002, 35: 21-31.View ArticlePubMedGoogle Scholar
  7. Hodge WG, Whitcher JP, Satariano W: Risk factors for age-related cataracts. Epidemiol Rev. 1995, 17: 336-346.PubMedGoogle Scholar
  8. Taylor HR: Epidemiology of age-related cataract. Eye. 1999, 13 (Pt 3b): 445-448.View ArticlePubMedGoogle Scholar
  9. DeBlack SS: Cigarette smoking as a risk factor for cataract and age-related macular degeneration: a review of the literature. Optometry. 2003, 74 (2): 99-110.PubMedGoogle Scholar
  10. Jacques PF, Moeller SM, Hankinson SE: Weight status, abdominal adiposity, diabetes, and early age-related lens opacities. Am J Clin Nutr. 2003, 78: 400-405.PubMedGoogle Scholar
  11. Glynn R, Christen W, Manson JE: Body mass index: an independent predictor of cataract. Arch Ophthalmol. 1995, 113: 1131-1137. 10.1001/archopht.1995.01100090057023.View ArticlePubMedGoogle Scholar
  12. Hennis A, Wu SY, Nemesure B: Risk factors for incident cortical and posterior subcapsular lens opacities in the Barbados Eye Studies. Arch Ophthalmol. 2004, 122: 525-530. 10.1001/archopht.122.4.525.View ArticlePubMedGoogle Scholar
  13. Nirmalan PK, Tielsch JM, Katz J: Relationship between vision impairment and eye disease to vision-specific quality of life and function in rural India: the Aravind Comprehensive Eye Survey. Invest Ophthalmol Vis Sci. 2005, 46: 2308-2312. 10.1167/iovs.04-0830.View ArticlePubMedGoogle Scholar
  14. Polack S, Kuper H, Mathenge W: Cataract visual impairment and quality of life in a Kenyan population. Br J Ophthalmol. 2007, 91: 927-932. 10.1136/bjo.2006.110973.View ArticlePubMedPubMed CentralGoogle Scholar
  15. Vita AJ, Richard B, Terry HB, Hubert D, James F: Aging, health risks, and cumulative disability. New Engl J Med. 1998, 3 (15): 38-42.Google Scholar
  16. Ghana Health Service Annual Report: Annual report of the Ghana Health Service, 2012. 2013, Accra, Ghana: Published by the Ghana Health ServiceGoogle Scholar
  17. Department of Community Health, University of Ghana Medical School: Ghana National Report on World Health Organization’s Study on global AGEing and adult health (SAGE) in Ghana, Wave 1. 2012, Geneva: WHOGoogle Scholar
  18. Kowal P, Chatterji S, Naidoo N, Biritwum R, Wu F, Lopez Ridaura R, Maximova T, Arokiasamy P, Phaswana-Mafuya N, Williams S, Snodgrass JJ, Minicuci N, D'Este C, Peltzer K, Boerma JT, SAGE Collaborators: Data resource profile: the world health organization study on global AGEing and adult health (SAGE). Int J Epidemiol. 2012, 1-11. doi:10.1093/ije/dys210Google Scholar
  19. National Health Insurance Authority , Ghana: Annual report of the national health insurance scheme of Ghana (2010). 2011, Ghana: Published by the National Health Insurance Authority (NHIA),Google Scholar
  20. Biritwum RB, Mensah G, Minicuci N, Yawson AE, Naidoo N, Chatterji S, Kowal P: Study on global AGEing and adult health in Ghana: Methodology and household characteristics in Wave 1. Glob Health Action. 2013, 6: 20096-http://dx.doi.org/10.3402/gha.v6i0.20096,PubMedGoogle Scholar
  21. Yawson AE, Baddoo A, Hagan-Seneadza NA, Calys-Tagoe B, Hewlett S, Dako-Gyeke P, Mensah G, Minicuci N, Naidoo N, Chatterji S, Kowal P, Biritwum R: Tobacco use in older adults in Ghana: sociodemographic characteristics, health risks and subjective wellbeing. BMC Pub Health. 2013, 13: 979-10.1186/1471-2458-13-979. 10.1186/1471-2458-13-979View ArticleGoogle Scholar
  22. WHO Library Cataloguing-in-Publication Data: Global Initiative for the Elimination of Avoidable Blindness. 2007, World Health Organization, Geneva, Switzerland: action plan, 2006-2011.Google Scholar
  23. Tsai SY, Hsu WM, Cheng CY, Liu JH, Chou P: Epidemiologic study of age-related cataracts among an elderly Chinese population in Shih-Pai, Taiwan. Ophthalmology. 2003, 110 (6): 1089-1095. 10.1016/S0161-6420(03)00243-4.View ArticlePubMedGoogle Scholar
  24. Mukesh BN, Le A, Dimitrov PN, Ahmed S, Taylor HR, McCarty CA: Development of cataract and associated risk factors: the Visual Impairment Project. Arch Ophthalmol. 2006, 124 (1): 79-85. 10.1001/archopht.124.1.79.View ArticlePubMedGoogle Scholar
  25. Currat LJ, de Francisco A, Al-Tuwaijri S, Al-Tuwaijri A, Jupp S, Global Forum for Health Research: Helping correct the 10/90 gap. The 10/90 Report on Health Research 2003–2004. 2004, Geneva, Switzerland: Published by Global Forum for Health ResearchGoogle Scholar
  26. World Health Organization: Global strategy on diet, physical activity and health. 2004, Geneva: Published by the World Health OrganizationGoogle Scholar
  27. Polack S, Kuper H, Wadud Z, Fletcher A, Foster A: Quality of life and visual impairment from cataract in Satkhira district, Bangladesh. Br J Ophthalmol. 2008, 92: 1026-1030. 10.1136/bjo.2007.134791.View ArticlePubMedGoogle Scholar
  28. Adamson J, Lawlor DA, Ebrahim S: Chronic disease, locomotor activity limitation and social participation in older women: Cross sectional survey of British Women's Heart and Health Study. Age Ageing. 2004, 33 (3): 293-298. 10.1093/ageing/afh090.View ArticlePubMedGoogle Scholar
  29. LaForge RG, Spector WD, Sternberg J: The relationship of vision and hearing impairment to one-year mortality and functional decline. J Aging Health. 1992, 4: 126-148. 10.1177/089826439200400108.View ArticleGoogle Scholar
  30. Ghana Statistical Service: Ghana Living Standards Survey Report of the Fifth Round, [September 2005- September 2006]. 2008, Accra: Ghana Statistical Service,Google Scholar
  31. National Health Insurance Authority, Ghana: Ghana National Health Insurance Act 650 of the Republic of Ghana. 2003, Accra, Ghana: Published by the Ghana Assembly PressGoogle Scholar
  32. Ederer F, Hiller R, Taylor HR: Senile lens changes and diabetes in two population studies. Am J Ophthalmol. 1981, 91 (3): 381-395.View ArticlePubMedGoogle Scholar
  33. Janghorbani M, Jones RB, Allison SP: Incidence of and risk factors for cataract among diabetes clinic attenders. Ophthalmic Epidemiol. 2000, 7 (1): 13-25. 10.1076/0928-6586(200003)711-2FT013.View ArticlePubMedGoogle Scholar
  34. Andresen E, Malmstrom TK, Miller DK, Miller JP, Wolinsky FD: Retest reliability of self-reported function, self-care and disease history. Med Care. 2005, 43 (1): 93-97.PubMedGoogle Scholar
  35. Pre-publication history

    1. The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2458/14/949/prepub

Copyright

© Yawson et al.; licensee BioMed Central Ltd. 2014

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 credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.