ABSTRACT
Postmenopausal Hispanic/Latina (N = 254) women with a body mass index (BMI) ≥ 25 kg/m2 were randomized to an intervention to reduce sitting time or a comparison condition for 12 weeks. The standing intervention group received three in-person health-counseling sessions, one home visit, and up to eight motivational interviewing calls. The heart healthy lifestyle comparison group (C) received an equal number of contact hours to discuss healthy aging. The primary outcome was 12-week change in sitting time measured via thigh-worn activPAL. Group differences in outcomes were analyzed using linear mixed-effects models. Participants had a mean age of 65 (6.5) years, preferred Spanish language (89%), BMI of 32.4 (4.8) kg/m2, and sat for an average of 540 (86) minutes/day. Significant between-group differences were observed in reductions of sitting time across the 12-week period [Mdifference (SE): C - 7.5 (9.1), SI - 71.0 (9.8), p < 0.01]. Results demonstrate that coaching models to reduce sitting are feasible and effective.
ABSTRACT
Time spent sitting is positively correlated with endothelial dysfunction and cardiovascular disease risk. The underlying molecular mechanisms are unknown. MicroRNAs contained in extracellular vesicles (EVs) reflect cell/tissue status and mediate intercellular communication. We explored the association between sitting patterns and microRNAs isolated from endothelial cell (EC)-derived EVs. Using extant actigraphy based sitting behavior data on a cohort of 518 postmenopausal overweight/obese women, we grouped the woman as Interrupted Sitters (IS; N = 18) or Super Sitters (SS; N = 53) if they were in the shortest or longest sitting pattern quartile, respectively. The cargo microRNA in EC-EVs from the IS and SS women were compared. MicroRNA data were weighted by age, physical functioning, MVPA, device wear days, device wear time, waist circumference, and body mass index. Screening of CVD-related microRNAs demonstrated that miR-199a-5p, let-7d-5p, miR-140-5p, miR-142-3p, miR-133b level were significantly elevated in SS compared to IS groups. Group differences in let-7d-5p, miR-133b, and miR-142-3p were validated in expanded groups. Pathway enrichment analyses show that mucin-type O-glycan biosynthesis and cardiomyocyte adrenergic signaling (P < 0.001) are downstream of the three validated microRNAs. This proof-of-concept study supports the possibility that CVD-related microRNAs in EC-EVs may be molecular transducers of sitting pattern-associated CVD risk in overweight postmenopausal women.
