The burden of obesity on blood pressure is reduced in older persons: The SardiNIA study

Introduction: Being overweight or obese increases the risk of elevated blood pressure. However differences of their effects on blood pressure in different age groups are not clear. Objective: The aim of the present study was to evaluate differences of the effects of adiposity on the odds of having hypertension in different age groups. Design and Methods: Three thousand fifty-six subjects (1,532 women and 1,524 men) consist of the drug naive subjects from the SardiNIA study. Logistic regression models with backward elimination were used to determine and compare the association between categories of obesity on hypertension within young (≤39), middle aged (40-59), and older (60+) subjects. Additional terms controlled for in the model were smoking and alcohol intake status. Results: The relationship of body mass index (BMI) on hypertension differed by age, as indicated by the significant interaction term of age with BMI (P <0.01). Older subjects had higher odds of having hypertension than younger subjects but these odds were lower for obese than for lean subjects (OR 10.45, 95% CIs 4.58-23.85 in obese versus OR 33.89, 95% CIs 17.94-64.02 in lean subjects). A similar trend was also observed in middle aged subjects. Conclusions: This study shows that among men and women, older age was associated with a lesser effect of BMI on the odds of having hypertension.