Obesity and leisure time physical activity (LTPA) are strongly and inversely associated in men with the Lewis (a-b-) phenotype - not in men with other Lewis phenotypes

Abstract

P73 Background Obesity is more prevalent among men with the Lewis (a-b-) phenotype than among others. It has recently been shown in the Copenhagen Male Study (CMS) that an excess risk of fatal IHD in Le(a-b-) men is strongly modified by LTPA. It has been disputed if LTPA is able to reduce or eliminate obesity. To elucidate this issue further, we hypothesized that a stronger inverse associaion exists between LTPA and obesity in Le(a-b-) men than in other men. Methods A historical prospective study of 2,824 Caucasian men free from overt IHD aged 53 to 75 years, examined in 1970 and 1985 in CMS. A low level of LTPA was defined as ≤4 hours/week moderate or ≤2 hour/week more vigorous physical activity. Main outcome: body mass index (BMI, kg/m 2 ). Results 266 men had the Le(a-b-) phenotype, 2,558 had other Lewis phenotypes and were pooled for analytical purposes. Le(a-b-) men had a higher BMI than other Lewis phenotypes, 26.1 vs 25.6, p<0.05. The table shows a strong inverse association between LTPA and BMI in Le(a-b-) men and an only weak association among others. Weight differences among sedentary men were 9.1 kg, among active 0.1 kg. Correlation coefficients for Le(a-b-) men: -0.27, for others: -0.07, a highly significant difference, p=0.008. Potential confounders did not explain this. Conclusions There was a strong inverse association between LTPA and BMI in Le(a-b-) men, an association not found among others. Public health and clinical implications may be important in eg US and Scandinavia, populations with a high prevalence of obesity, a predominantly sedentary lifestyle, and a high proportion of Le(a-b-) men. Table 1.