Introduction Obesity is associated with reduced quality of life (QOL), particularly physical health. In addition obesity has been linked to reduced exercise and high calorie diet. We aimed to describe these factors in obese individuals with and without ventilatory failure, and investigate the hypothesis that ventilatory failure would have a negative impact on QOL.

Methods QOL, diet and exercise was assessed as part of an open cross-sectional study of ventilatory failure in obese subjects referred either for assessment of sleep disordered breathing or bariatric surgery.

The SF-12 was completed; a validated questionnaire to assess QOL giving summary scores for physical health (PCS) and mental health (MCS), and compared to data from a large non-obese UK cohort.¹

Participants underwent actigraphy (SenseWear BodyMedia) and from this the daily energy expenditure was estimated. A sedentary lifestyle was defined as <5000 steps/day.

Participants completed a validated food frequency questionnaire, which calculates daily dietary calorie intake from patient reported three month food habits. This was compared to UK guideline recommended daily maximum intake.

Arterial base excess was measured as a marker of ventilatory failure and the correlations between quality of life indices and arterial base excess were calculated.

Results 72 individuals with a mean age of 52.0 years (SD 8.9) and median BMI of 46.7 kg/m² (IQR 39.5, 52.6) participated in the study. Median duration of actigraphy was 23.2 days (IQR 21.2, 23.4).

Arterial base excess was significantly but weakly correlated to MCS (r = 0.33, p = 0.01) but not to PCS (r = 0.05, p = 0.74).

Conclusions Obesity had a large negative impact on both physical and mental QOL not reproducibly reported elsewhere. Ventilatory failure was only a weak predictor of mental, but not physical QOL scores. The majority of participants were sedentary and dietary calorie intake was higher than the recommended daily allowance for most women and a significant number of men. Actigraphy energy expenditure estimates exceeded patient reported dietary intake, which is probably due to patient underreporting. This highlights the clinical importance of considering mental health, physical activity and diet together when obese individuals are seen in a tertiary centre.

Reference 1 J Pub Health Med. 2001;23:187–94