Introduction: Obesity is a primary risk factor for obstructive sleep apnea (OSA), and weight loss is a common recommendation for adults with OSA. However, we previously found that adults with OSA lost less weight than those without OSA during a 12-month behavioral weight loss intervention. The potential mechanisms underlying the blunted weight loss among those with OSA are currently unclear; however, one potential explanation may be lower adherence to the intervention and its prescribed behaviors.
Purpose: These analyses examined whether measures of adherence to a behavioral weight loss intervention differed between adults with and without OSA.
Methods: The sample was comprised of adults who were overweight or obese (N=114; 50.4±10.5 y, body mass index [BMI]: 34.0±4.6 kg/m2; 90.4% female, 82.5% white) who participated in a 12-mo behavioral weight loss intervention study. Participants wore a home sleep testing device (ResMed ApneaLink Plus) for one night at baseline (BL), 6 mo (6M), and 12 mo (12M). Those with an apnea-hypopnea index ≥ 5 were categorized as having OSA. Adherence to the intervention was assessed by: 1) attendance at group intervention sessions over 12 mo; 2) frequency of meeting daily caloric intake goals over 12 mo; 3) objectively-measured changes from BL in physical activity (steps/day, sedentary time, moderate-vigorous physical activity [MVPA]). Linear mixed models estimated the impact of OSA on these measures of intervention adherence following adjustment for sex, age, race, marital status, smoking status, and baseline BMI, while considering participant to be a random effect.
Results: About half (52%) of the participants had OSA at BL, while 41 % had OSA at 6M. Attendance at group sessions did not differ between those with and without OSA over 12 mo (74.5 vs. 75.7%; P=.72). However, adults with OSA met their caloric intake goal less frequently than those without OSA (25.2 vs. 34.8%; P=.006), and adults with OSA increased their steps/day (+378.3 vs. 1060.1; P=.047) and MVPA min/day (+2.1 vs. +6.4; P=.056) less than those without OSA. Reductions in sedentary behavior (min/day) did not differ between those with and without OSA (-7.1 vs. -9.1; P=.81).
Conclusions: These data suggest that the blunted weight loss observed among adults with OSA may be at least partially attributable to lower levels of adherence to prescribed goals for caloric intake and physical activity. Additional strategies (e.g., OSA screening and treatment referral, supplemental sessions on diet and MVPA) may be needed to achieve improved adherence to the lifestyle behaviors that lead to weight loss among adults with OSA.