Sleep duration and incidence of hypertension in the Bandare-Kong cohort study: findings from PERSIAN cohort study

BACKGROUND: Hypertension remains a major global public health concern. Emerging evidence suggests that sleep duration may play a significant role as a modifiable risk factor; however, findings across studies have been inconsistent. This study aims to examine the association between sleep duration and hypertension in a cohort of adults residing in southern Iran. METHODS: This population-based study was conducted among adults aged 35-70 years from the Bandare-Kong Non-Communicable Diseases (BKNCD) Cohort, part of the Prospective Epidemiological Research Studies in Iran (PERSIAN). Blood pressure was measured using a standardized protocol, and hypertension was defined as systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic blood pressure (DBP) ≥ 90 mmHg or the use of antihypertensive medication. Sleep duration was self-reported through a structured questionnaire. Logistic and Cox regression models were applied to assess the association between sleep duration and hypertension. Analyses were performed using R software, with p-values < 0.05 considered statistically significant. RESULTS: A total of 3,737 participants were included in the analyses, among whom 1,332 individuals without hypertension at baseline were followed for six years. At baseline, logistic regression analysis showed that women under the age of 50 who reported sleeping less than 7 h per night had 1.82 times higher odds of having hypertension compared to those who slept 7-8 h per night (OR = 1.82; 95% CI: 1.31-2.15; p = 0.042). Among participants aged 50 years and older, both women and men with short sleep duration (< 7 h/night) had significantly increased odds of hypertension compared to their counterparts who slept 7-8 h per night (women: OR = 2.68; 95% CI: 1.52-3.88; p < 0.001; men: OR = 2.35; 95% CI: 1.45-4.00; p = 0.003). Furthermore, Cox proportional hazards modeling indicated that individuals with either short (< 7 h) or long (> 8 h) sleep duration had a 1.91-fold increased risk of developing hypertension over the study period compared to those with normal sleep duration (7-8 h/night) (HR = 1.91; 95% CI: 1.84-3.50; p = 0.041). CONCLUSIONS: Both short sleep duration (< 7 h/night) and long sleep duration (> 8 h/night) were associated with an increased risk of hypertension. These findings highlight the importance of adequate sleep as a potential modifiable factor in hypertension prevention. Future research is warranted to further explore the combined impact of sleep duration and sleep quality on the development of hypertension.