BODY-FAT AND STROKE - UNMASKING THE HAZARDS OF OVERWEIGHT AND OBESITY

Study objective - It has been frequently noted that overweight and obe sity have a stronger relationship to hypertension and diabetes mellitu s than to the risk of stroke. The reason for this observation has not been clear. This study aimed to examine the lifelong relation between body fat and stroke to shed light on why the public health risks of ov erweight and obesity have tended to be obscured in previous epidemiolo gical studies. Design - Case-control study. Setting - Eleven general p ractices in west Birmingham. Participants - Altogether 125 men and wom en who had just had their first stroke and were aged 35-74 years and 1 98 controls frequency matched for age and sex were recruited over 24 m onths during 1988-90. Main results - Those in both the thinnest and fa ttest quartiles of subscapular skinfold thickness were at increased ri sk of stroke compared with those in the middle quartiles (age adjusted odds ratios 2.12 (95% confidence interval (CI) 1.2, 3.9) and 2.08 (1. 1, 3.8) respectively). When Lifelong maximum reported body mass index was assessed the hazards of obesity but not leanness were seen (odds r atio for the highest versus the lowest quartile were - age adjusted, 1 .54 (0.8, 3.0) and multiple risk factor adjusted, 2.25 (1.1, 4.5). Thi s lifelong pattern of risk seemed to be established early, the odds ra tios for the highest versus the lowest quartile of reported body mass index aged 21 years were - age adjusted, 2.18 (1.1, 4.4) and multiple risk factor adjusted 2.13 (1.1, 4.2). The risks of both maximum report ed body mass index and reported body mass index aged 21 years were mor e clear in those who had never smoked cigarettes (test for trend in od ds ratio, p = 0.009 and p = 0.02 respectively). Conclusions - Potentia lly important risks of excessive body fat for stroke can be obscured b y both a history of cigarette smoking and thinness associated with det eriorating health. The results seem to explain why excess body fat has previously been consistently related to hypertension and diabetes mel litus but less consistently to stroke. Avoiding overweight and obesity during adult life offers protection against stroke.