Does leptin predict incident hypertension in older adults?

Abstract

Objective: Leptin is associated with blood pressure (BP) in experimental and cross-sectional studies, but only one previous prospective study of middle-aged men has reported the association between leptin and incident hypertension. We examined the association of leptin levels with incident hypertension in a population-based study of older men and women.

Design: Longitudinal cohort study.

Population: Participants were 602 community-dwelling older adults with normal baseline BP levels who attended a research clinic visit between 1984 and 1987 and again 4.4 years later (mean age was 66.2 +/- 11.4; 60.6% were men; mean body mass index (BMI) 24.9 +/- 3.4 kg/m(2)).

Measurements: Hypertension was defined as systolic BP > or =140 mmHg and/or diastolic BP > or =90 mmHg and/or antihypertensive drug treatment. Leptin was measured by radioimmunoassay.

Results: After an average 4.4-year follow-up (minimum 2-maximum 7 years), 106 (17.6%) new cases of hypertension were identified. At baseline, participants who developed hypertension were older and had higher systolic BP and higher total cholesterol compared to participants who remained normotensive. Baseline serum leptin levels were higher in participants who developed hypertension compared to persistent normotensives [median (25th-75th range)] [8.8(5-16) vs 7(4-11) ng/ml, P = 0.002]. In logistic regression models, leptin (log-transformed) predicted incident hypertension before and after adjustments for baseline age, BMI, systolic BP, total cholesterol, medications, and previous cardiovascular disease (OR 1.75 95% CI 1.17-2.61, P = 0.006). This association persisted after exclusion of 45 obese participants.

Conclusion: Higher leptin levels were independently associated with increased odds of incident hypertension in older adults.

Figure 1

Odds ratio for incident hypertension, highest tertile of leptin compared to the lowest tertile (reference category). Model 1: adjusted for age and body mass index; Model 2: model 1 + baseline systolic blood pressure + total cholesterol; Model 3: model 2 + medication (aspirin, cholesterol-lowering, and estrogen therapy in women); Model 4: model 3 + previous cardiovascular disease.