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Table 4 Logistic regression models for the health dimensions mobility, self-care, activities, pain and anxiety

From: Association between body mass index and health-related quality of life, and the impact of self-reported long-term conditions – cross-sectional study from the south Yorkshire cohort dataset

Beta coefficients Mobility Self-care Activities Pain Anxiety/Depression †
Sample size (n) 19,217 19,090 19,207 19,134 18,973
BMI-2 19.13 (10.58 to 34.54) 19.26 (9.47 to 39.17) 13.24 (7.67 to 22.83) 8.4 (5.05 to 13.97) 8.65 (4.15 to 18.01)
BMI-1 0.06 (0.04 to 0.09) 0.07 (0.04 to 0.13) 0.1 (0.06 to 0.15) 0.13 (0.09 to 0.2) 0.06 (0.02 to 0.15)
Age* 1.04 (1.04 to 1.04) 1.02 (1.01 to 1.02) 1.02 (1.02 to 1.03) 3.82 (3.39 to 4.26) 0.56 (0.49 to 0.63)
Deprivation 1.01 (1.01 to 1.02) 1.02 (1.01 to 1.02) 1.01 (1.01 to 1.02) 1.01 (1.01 to 1.01) 1.01 (1.01 to 1.01)
Male gender 1.21 (1.11 to 1.32) 1.27 (1.11 to 1.45)    0.70 (0.96 to 0.97)
Non-white ethnicity      0.87 (0.97 to 1.01)
Alcohol status      
 Moderate drinker 0.64 (0.59 to 0.7) 0.53 (0.47 to 0.61) 0.66 (0.61 to 0.73) 0.76 (0.7 to 0.82) 0.76 (0.96 to 0.98)
 Heavy drinker 0.57 (0.49 to 0.67) 0.36 (0.28 to 0.48) 0.58 (0.5 to 0.67) 0.76 (0.67 to 0.84) 0.85 (0.97 to 1)
Highest education      
 A-levels / NVQ3 1.4 (1.2 to 1.65) 1.48 (1.12 to 1.97) 1.17 (1.01 to 1.36) 1.58 (1.4 to 1.77) 1.3 (1.01 to 1.04)
 GCSE / NVQ1-2 1.34 (1.19 to 1.52) 1.38 (1.09 to 1.73) 1.17 (1.04 to 1.32) 1.58 (1.45 to 1.73) 1.34 (1.02 to 1.04)
 Other 1.65 (1.39 to 1.95) 2.51 (1.92 to 3.25) 1.46 (1.23 to 1.73) 1.79 (1.55 to 2.08) 1.31 (1.01 to 1.04)
 None 1.9 (1.67 to 2.16) 2.41 (1.93 to 2.97) 1.57 (1.38 to 1.77) 2.03 (1.84 to 2.25) 1.45 (1.03 to 1.05)
Smoking status      
 Current 2.01 (1.77 to 2.27) 2.08 (1.73 to 2.48) 2.08 (1.84 to 2.34) 1.52 (1.38 to 1.68) 1.75 (1.05 to 1.07)
 Former 1.25 (1.13 to 1.36) 1.17 (1.02 to 1.36) 1.26 (1.15 to 1.38) 1.27 (1.17 to 1.36) 1.17 (1.01 to 1.02)
Long-term conditions      
 Diabetes 1.62 (1.39 to 1.88) 1.26 (1.04 to 1.52) 1.4 (1.22 to 1.63) 1.22 (1.05 to 1.4) 1.25 (1.01 to 1.04)
 Heart disease 2.36 (2.03 to 2.75) 1.92 (1.6 to 2.27) 2.75 (2.39 to 3.19) 1.67 (1.43 to 1.95) 1.45 (1.02 to 1.05)
 Stroke 2.27 (1.75 to 2.94) 2.53 (1.93 to 3.32) 2.8 (2.18 to 3.6) 1.43 (1.11 to 1.86) 1.48 (1.02 to 1.06)
 Cancer 1.92 (1.55 to 2.36) 1.9 (1.46 to 2.46) 2.12 (1.73 to 2.61) 1.55 (1.27 to 1.9) 1.35 (1.01 to 1.05)
 Osteoarthritis 5.81 (5.16 to 6.62) 3.35 (2.89 to 3.86) 4.31 (3.86 to 4.85) 12.81 (10.49 to 15.49) 1.6 (1.04 to 1.06)
 Breathing problems 2.53 (2.27 to 2.86) 2.36 (2.03 to 2.72) 2.64 (2.34 to 2.94) 1.82 (1.63 to 2.05) 1.65 (1.04 to 1.06)
 High blood pressure 1.27 (1.16 to 1.4) 1.28 (1.12 to 1.49) 1.23 (1.12 to 1.36) 1.16 (1.05 to 1.27) 1.15 (1.01 to 1.02)
Constant −2.33 (−2.46 to −2.21) −3.85 (−4.06 to −3.63) −2.07 (−2.18 to −1.96) −0.86 (−0.95 to −0.77) −1.37 (−1.57 to −1.17)
BMI value for minimum problems. 20.73 22.49 22.15 20.98 23.94
AUROC 0.844 0.849 0.801 0.778 0.656
Statistical significance; all variables in the model have p < 0.001 except: - Male(0.001), A-levels (0.006), GCSEs (0.006), former smoking (0.025), diabetes (0.018) A-levels (0.038), GCSEs (0.008). Diabetes (0.008), stroke (0.008) , high blood pressure (0.002) Alcohol heavy drinker (0.011), Ethnicity: Non-white (0.139) Highest education; other, diabetes, stroke (all 0.001), cancer (0.002), high blood pressure (0.003)
Approximate odds-ratios (95% confidence interval) per unit change**:
Underweight 1.09 (0.91 to 1.29) 1.21 (0.98 to 1.48) 1.10 (0.94 to 1.29) 1.01 (0.88 to 1.16) 1.05 (0.93 to 1.20)
Overweight 1.08 (1.03 to 1.13) 1.04 (0.97 to 1.13) 1.06 (1.01 to 1.11) 1.12 (1.75 to 1.16) 1.03 (0.99 to 1.07)
Obese 1.08 (1.06 to 1.10) 1.06 (1.03 to 1.08) 1.06 (1.04 to 1.08) 1.05 (1.03 to 1.07) 1.03 (1.01 to 1.05)
  1. AUROC – Area under the receiver operating characteristic curve, BMI: Body mass index. Values in brackets are 95% confidence intervals.
  2. The constant term applies to 54.28 year old white females who do not smoke, have not consumed alcohol in the last week, hold a degree or NVQ4-5, have no long-term conditions, a deprivation score of 27.05 and a BMI of 26.29.
  3. *Age is linear for Mobility, Self-Care and Activities and Ln(Age/10) for Pain. All continuous variables are centred; additionally the two BMI variables have been scaled (divided by 10). Odds ratios are per 0.1 increase.
  4. The continuous variables BMI and Age are modelled differently for anxiety/depression. The term ‘BMI-2’ is replaced with ‘BMI-0.5’. The stated coefficient for age corresponds to (Age/10)-1. An additional term for age is also necessary; (Age/10)0.5. This has odds ratio 0.86 (0.83 to 0.89). For anxiety/depression the two odds ratios for age are per 0.1 increase.
  5. **These odds ratios were estimated by assuming separate linear trends amongst those underweight, overweight, and obese. These values should not be used when making predictions. To increase numbers in the underweight category, a BMI value < 20 was taken as being underweight.