Rationale: Obstructive sleep apnea and systemic hypertension (SH) are highly prevalent. Although their association has been suggested in cross-sectional studies, conflicting evidence has emerged from longitudinal studies. Objectives: To assess the association between obstructive sleep apnea and SH in the middle-aged general population. Methods: A total of 2,148 subjects were included in a longitudinal study of the Vitoria Sleep Cohort, a general population sample aged 30-70 years. We analyzed

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... ta on office blood pressure, anthropometric measures, health history, and home polygraphy. Out of 1,557 subjects who completed the 7.5-year follow-up, 377 were excluded for having SH at baseline. The odds ratios for the incidence of SH, according to the respiratory disturbance index (RDI) at baseline, were estimated in 1,180 subjects (526 men and 654 women) after adjustment for age; sex; body mass index; neck circumference; fitness level; and alcohol, tobacco, and coffee consumption. The RDI was divided into quartiles (0-2.9, 3-6.9, 7-13.9, and > 14), using the first quartile as reference. Measurements and Main Results: The crude odds ratio for incident hypertension increased with higher RDI category with a doseresponse effect (P , 0.001), but was not statistically significant after adjustment for age (P ¼ 0.051). Adjustments for sex (P ¼ 0.342), body mass index (P ¼ 0.803), neck circumference (P ¼ 0.885), and fitness level and alcohol, tobacco, and coffee consumption (P ¼ 0.708) further reduced the strength of the association between RDI and SH. No differences were observed between men and women. Conclusions: Our findings do not suggest an association between obstructive sleep apnea and the incidence of SH in the middle-aged general population. Long-term follow-up longitudinal studies are needed to better ascertain this association. The association between obstructive sleep apnea and systemic hypertension has been suggested in several crosssectional studies, and in continuous positive airway pressure intervention trials. To date, however, only two observational longitudinal studies have examined this association, with conflicting results. What This Study Adds to the Field This prospective study does not support a causal relationship between obstructive sleep apnea and systemic hypertension in the middle-aged general population.