CURRENT OBESITY, STEADY WEIGHT CHANGE AND WEIGHT FLUCTUATION AS PREDICTORS OF PHYSICAL FUNCTIONING IN MIDDLE-AGED OFFICE WORKERS - THE WHITEHALL-II STUDY

OBJECTIVES: (i) To investigate the effects of current obesity, steady weight change and weight fluctuation on physical functioning and (ii) to determine whether associations are independent of coronary heart di sease. DESIGN: Prospective cohort study with body mass index (BMI) mea surements at four time points between the ages of 25 and 63 y. SETTING : British civil servants based in London offices at baseline. PARTICIP ANTS: 6895 men and 3413 women aged 35-55 y at baseline. MAIN OUTCOME M EASURE: Physical functioning was assessed using the 10-item scale from the Short Form 36 Health Survey, with a score in the lowest quartile indicating poor physical functioning. RESULTS: After adjustment for ag e and confounders (employment grade, smoking, alcohol, exercise and me nopausal status), current BMI was monotonically associated with poor p hysical functioning in women whereas a threshold effect at a BMI of 27 kg/m(2) was seen in men. The odds ratio of poor physical functioning was 1.55 (95% confidence interval (CI) 1.02-2.35) amongst women and 1. 04 (95% CI 0.77-1.41) amongst men with BMI 23-24.9 kg/m(2) compared to those with BMI < 21 kg/m(2). Women in the upper, compared to the lowe r, tertile of steady weight change, had an odds ratio of poor physical functioning of 1.79 (1.24-2.60) after adjustment for age, confounders , current BMI and weight fluctuation. Women in the upper, compared to the lower, tertile of weight fluctuation had an odds ratio of poor phy sical functioning of 1.70 (1.23-2.34) adjusting for age, confounders, current BMI and steady weight change. Adjustment for the presence of c oronary heart disease did not substantially alter any of these associa tions. Steady weight change and weight fluctuation had no independent effects in men. CONCLUSION: Among women, current obesity, steady weigh t change and weight fluctuation are independently and monotonically as sociated with poor physical functioning. Development of overt coronary heart disease is unlikely to be the mechanism for these associations.