Abstract
BACKGROUND: The association between different sedentary behaviors and hypertension risk remains unclear. We aimed to explore the relationship between different domains of sedentary behaviors and new-onset hypertension, investigate whether genetic susceptibility to hypertension modifies the relationship, and examine the extent to which the relationship is mediated by body mass index (BMI) and grip strength.
METHODS: 212 714 participants without baseline hypertension in the UK Biobank were enrolled. The three major sedentary behaviors (TV-watching, nonoccupational computer use, and driving) were measured using touch screen questionnaires. The primary outcome was new-onset hypertension.
RESULTS: During a median follow-up of 11.9 years, 13 983 participants developed hypertension. There was a linear positive association between TV-watching time and new-onset hypertension (p for nonlinearity =0.868). A J-shaped association was found for nonoccupational computer use time and driving time with new-onset hypertension, with an inflection point of 0.5 h/day for both (both p for nonlinearity <0.001). Polygenetic risk scores for hypertension (based on 118 related single-nucleotide polymorphisms) did not significantly modify these associations (all p-interactions >0.05). Furthermore, the detrimental effects of long-term sedentary behaviors on hypertension were mediated by BMI by 21%-30%, and the beneficial effects of limited sitting time (within 0.5 h/day) for driving and nonoccupational computer use were mediated by grip strength by 6-25%.
CONCLUSIONS: There was a positive association for hands-independence sedentary behavior (TV-watching), and a J-shaped association for hands-dependence sedentary behaviors (nonoccupational computer use and driving) with new-onset hypertension, regardless of genetic risks of hypertension. These relationships were partly mediated by BMI and grip strength.