Since 1980, obesity has more than doubled worldwide, and in 2008 over 1.5 billion adults aged 20 years were overweight.

Transcription

1 Impact of metabolic comorbidity on the association between body mass index and health-related quality of life: a Scotland-wide cross-sectional study of 5,608 participants Dr. Zia Ul Haq Doctoral Research Student Public Health Supervisors: Prof Jill Pell (Henry Mechan Professor of Public Health), Dr. Daniel Mackay & Dr. Elisabeth Fenwick, University of Glasgow.

2 Introduction Since 1980, obesity has more than doubled worldwide, and in 2008 over 1.5 billion adults aged 20 years were overweight. In Scotland, around 2/3 of adult men and more than one-half of adult women are either overweight or obese, and in common with other developed countries, the prevalence is increasing. Overall obesity is associated with Morbidity, Life-expectancy, Economic burden & HRQoL Recent studies suggest that healthy obesity may not be associated with morbidity & mortality but its impact on HRQoL is not known 1

3 Aim of the Study We aim to use Scotland-wide data to explore the impact of healthy obesity on HRQoL. Data Source: Scottish Health Survey 2003 Inclusion criterion was aged 20 years Age (20-44, 45-64, 65 years) SF-12 responses converted to utility using SF-6d algorithm Scottish Index of Multiple Deprivation (SIMD) 2004 BMI category (World Health Organization definition) 2

4 Comorbidity Metabolic comorbidity (diabetes, hypertension, hypercholesterolemia or cardiovascular disease) Cardiovascular disease (angina or a past history of stroke or myocardial infarction) Hypertension ( 140/90 mmhg, or anti-hypertensive medication) Hypercholesterolemia (total cholesterol concentration 5.2mmol/L, or lipid-lowering medication) Smoking status (never, ex- or current smoker) Alcohol consumption (never, ex-, < 21 units/week for men, < 14 units/week for women or 21 units/week for men, 14 units/week for women) 3

5 Analysis All statistical analyses were performed using Stata version 11.2 Categorical data were summarized using frequencies and percentages, groups were compared using chi-square tests, or chi-square tests for trend for ordinal data. Univariate and multivariate linear regression models were used to examine the association between BMI category and utility score. Adjusting for age, sex, deprivation quintile, smoking status and alcohol consumption. Normal weight was used as the referent category. We tested whether there was a statistically significant interaction with metabolic comorbidity and stratified the analyses by the presence of metabolic comorbidity. The robustness of standard errors was checked using the bootstrapping method. 4

6 Underweight Normal - weight Overweight Obese Morbidly obese P-value Overall N=67 N(%) N=1,797 N(%) N=2,276 N(%) N=1,319 N(%) N=149 N(%) N=5,608 N(%) Age (years) (47.8) 937 (52.1) 858 (37.7) 440 (33.4) 54 (36.2) < ,321 (41.4) (31.3) 562 (31.3) 916 (40.3) 549 (41.6) 75 (50.3) 2,123 (37.9) Sex (20.9) 298 (16.6) 502 (22.1) 330 (25.0) 20 (13.4) 1, 164 (20.8) Male 26 (38.8) 688 (38.3) 1,183 (52.0) 598 (45.3) 36 (24.2) < ,531 (45.1) Female 41 (61.2) 1,109 (61.7) 1,093 (48.0) 721 (54.7) 113 (75.8) 3,077 (54.9) Metabolic comorbidity No 59 (88.1) 1,632 (90.8) 1,899 (83.4) 990 (75.0) 107 (71.8) < ,687 (83.6) Yes 8 (12.0) 165 (9.2) 377 (16.6) 329 (25.0) 42 (28.2) 921 (16.4) Smoking status Never 21 (31.3) 748 (41.6) 1, 002 (44.0) 599 (45.4) 60 (40.3) < , 430 (43.3) Ex- 7 (10.5) 409 (22.8) 737 (32.4) 447 (33.9) 56 (37.6) 1, 656 (29.5) Current 39 (58.2) 640 (35.6) 537 (23.6) 273 (20.7) 3 (22.2) 1, 522 (27.1)

7 SF-6D Score Percentage sf-6d preference-based measured of health Mean 0.79 Median 0.86 Mode 0.86 Standard Deviation 0.14 Range 0.66 Minimum 0.34 Maximum 1 Count 6559

8 No metabolic comorbidity Coefficient (95% CI) P-value With metabolic comorbidity Coefficient (95% CI) P-value BMI category Underweight (-0.069, ) (-0.245, ) Normal-weight* Overweight (-0.008, 0.009) (-0.002, 0.053) Obese (-0.026, ) (-0.043, 0.013) Morbidly obese (-0.069, ) < (-0.128, ) Age (yrs) (-0.002, 0.013) (-0.030, 0.043) (-0.020, 0.002) (-0.017, 0.024) Sex Male* Female (-0.027, ) < (-0.025, 0.015) Smoking status Never smoker* (-0.016, 0.001) (-0.053, ) Ex-smoker (-0.050, ) < (-0.095, ) <0.001 Current smoker Drinking status Never drinker* Ex-drinker (-0.075, ) < (-0.094, 0.008) Sensible drinker (-0.014, 0.021) (-0.02, 0.067) Excessive drinker Missing (-0.020, 0.018) (0.010, 0.093) (-0.130, 0.021) (-0.173, 0.239) 0.754

9 In relation to the association between BMI category and utility score, there was a significant interaction with metabolic comorbidity. In every BMI category, the utility score was lower among those with metabolic comorbidity. Among both individuals with and without metabolic comorbidity, there was an inverted U-shaped relationship. HRQoL was significantly reduced among obese individuals regardless of the presence or absence of metabolic comorbidity. After adjustment the utility score was non-significantly higher among overweight than normal weight individuals, irrespective of the presence of metabolic comorbidity. 8

10 Mean & 95%CI with NO comorbidity Mean & 95%CI with comorbidity Mean utility underweight normal-weight overweight obese morbidly obese Unadjusted: adopted from (Ul-Haq Z, Mackay D, Fenwick E, Pell J. Impact of comorbidity on the association between body mass index and health-related quality of life: a Scotland-wide cross-sectional study of 5,608 participants. BMC Public Health 2012, 12:143). 9

11 Conclusions Individuals with metabolic comorbidity have a poorer HRQoL than those without, irrespective of their BMI. However, HRQoL is significantly reduced among obese individuals even in the absence of metabolic comorbidity, suggesting that healthy obesity is a misnomer. Health extends beyond clinical events, to encompass psychological well-being. Our study suggests that obesity is a risk for reduced HRQoL, even in the absence of comorbid conditions. For further details (Ul-Haq Z, Mackay D, Fenwick E, Pell J. Impact of comorbidity on the association between body mass index and health-related quality of life: a Scotland-wide cross-sectional study of 5,608 participants. BMC Public Health 2012, 12:143). 10

12 Future work using SHS: Forecasting future BMI trends (aged year) obese overweight Proportions morbidly obese normal-weight Year 11

13 Future work Scottish population by BMI, age, sex and deprivation NO COMORBIDITY Diabetes Coronary Heart Diseases Arthritis Post-menopausal Breast Cancer Colon Cancer Death

14 Th 13