OBJECTIVE: In overweight-related hypertension, the effect of weight changes on blood pressure (BP) is believed to be mediated by insulin. To test this hypothesis, we studied 5-year changes in weight, BP, and insulin in a general population of Danish adults (n = 3443; mean age 45.7 ± 7.6 years).

METHODS: We assessed the glucose-insulin metabolism by a standard oral glucose tolerance test. We divided the antihypertensive and antidiabetic medication-free participants into three groups: weight loss (n = 515), weight stable (n = 1778), and weight gain (n = 1150).

RESULTS: Losing on average 6.5 kg body weight, the weight loss group experienced a 28.2% reduction [(95% confidence interval [CI] -31 to -25); P < 0.001] in fasting insulin and a 23.9% reduction [(95% CI -28 to -19); P < 0.001] in 2-h insulin. Gaining on average 6.4 kg, the weight gain group experienced a 12.5% increase [(95% CI 9 to 16); P < 0.001] in fasting insulin and 32.8% increase [(95% CI 28 to 38); P < 0.001] in 2-h insulin. Using linear regression adjusting for differences in sex, age, family history of hypertension, baseline BMI, SBP and DBP, lifestyle risk factors, and their 5-year changes, weight loss was associated with a decrease in SBP of -1.8 mmHg (95% CI -2.8 to -0.7), whereas weight gain with an increase in SBP of 1.9 mmHg (95% CI 1.2 to 2.6), both with P less than 0.001. Adding fasting insulin, 2-h insulin, Δfasting insulin, and Δ2-h insulin only marginally attenuated the association, and furthermore, none of the insulin variables was significantly associated with SBP or DBP (P ≥ 0.08). The results for changes in DBP were similar to SBP.

CONCLUSION: Five-year weight changes associate with BP alterations independent of the insulin changes.