Weight change and short-term risk of hypertension in healthy adults

BACKGROUND AND AIMS: Obesity is a major risk factor for hypertension, but most evidence relies on single weight measurements. We examined associations between weight change and short-term risk of incident hypertension across body mass index (BMI) categories. METHODS: We conducted a retrospective cohort study in the Danish Blood Donor Study of 81,954 participants aged 18-79 with at least two questionnaires (2010-2025). Weight change was the percentage difference between consecutive self-reported weights, grouped as stable, 2.5-5, 5-10, or more than 10% loss or gain. Incident hypertension was defined as first redemption of antihypertensive drugs. Associations were estimated using multivariable Cox models. RESULTS: During a median follow-up of 1.66 years (IQR 0.79-2.88; maximum 3 years), 5,503 participants initiated antihypertensive treatment. In BMI-stratified analyses, weight gain was associated with higher risk of initiation in all BMI categories, while weight loss was associated with lower risk only in overweight or obesity relative to stable weight. Across BMI categories using stable normal weight as reference, associations were stronger at higher BMI. More than 10% weight gain was associated with hazard ratios of 1.60 (95% CI 1.30-1.96) in normal weight, 2.44 (2.02-2.96) in overweight and 4.51 (3.57-5.70) in obesity. Hazard ratios were comparable across sex and age groups, although higher in younger men with obesity, while rates were highest in older participants. CONCLUSION: Weight gain was associated with higher risk of antihypertensive treatment across BMI categories compared with stable weight, whereas weight loss was inversely associated with initiation among adults with overweight or obesity.