Relations of Insulin Sensitivity to Longitudinal Blood Pressure Tracking

Abstract

Background— The relations of insulin sensitivity (IS) to hypertension incidence may vary according to baseline age, body mass index (BMI), and blood pressure (BP). Methods and Results— We investigated the relations of IS (insulin sensitivity index, ISI 0,120 ) to 4-year incidence of hypertension and BP progression in 1933 nonhypertensive Framingham Study participants (median age, 51 years; 56% women). Analyses were stratified by age (less than versus greater than or equal to median), BMI (<25 [normal], 25 to <30 [overweight], ≥30 kg/m 2 [obese]), and BP category (systolic BP≥130 or diastolic BP≥85, “high normal” per the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High BP [JNC-VI] versus BP<130/85 mm Hg). On follow-up, 41% of participants had BP progression (≥1 BP stage increase) and 18% had development of hypertension (systolic BP≥140 or diastolic BP≥90 mm Hg or antihypertensive medication use). In younger (<51 years) people with normal BMI and baseline BP<130/85 mm Hg, the second-to-fourth ISI 0,120 quartiles were associated with lower multivariable-adjusted odds for hypertension incidence (0.27; 95% CI, 0.09 to 0.83; P <0.05) and BP progression (0.37; 95% CI, 0.18 to 0.77; P <0.01) relative to the lowest (most insulin resistant) quartile. IS was not related to BP progression or hypertension incidence in older individuals, in obese participants, or in people with BP≥130/85 mm Hg. Conclusions— In our large community-based sample, reduced IS predicted BP tracking principally in younger people with normal BMI and BP<130/85 mm Hg. Effect modification by age, BMI, and baseline BP may explain variation in the results of prior clinical investigations relating IS to hypertension incidence.