Associations of lifestyle factors, disease history and awareness with health-related quality of life in a Thai population.

Background: The impact of the presence and awareness of individual health states on quality of life (HRQoL) is often documented. However, the impacts of different health states have rarely been compared amongst each other, whilst quality of life data from Asia are relatively sparse. We examined and compared the effects of different health states on quality of life in a Thai population.

Methods: In 2008-2009, 5,915 corporate employees were invited to participate in a survey where HRQoL was measured by the Short Form 36 (SF-36) questionnaire. The adjusted mean SF-36 scores were calculated for each self-reported illness, number of chronic conditions, lifestyle factors and awareness of diabetes and hypertension. The effect sizes (ES) were compared using Cohen's d.

Results: The response rate was 82% and 4,683 (79.1%) had complete data available for analysis. Physical and Mental Component Summary (PCS and MCS) scores decreased as the number of chronic conditions increased monotonically (p<0.0001). Diabetes and hypertension negatively influenced PCS (mean score differences -0.6 and -1.5, p<0.001 respectively) but not MCS, whereas awareness of diabetes and hypertension negatively influenced MCS (-2.9 and -1.6, p<0.005 respectively) but not PCS. Arthritis had the largest ES on PCS (-0.37), while awareness of diabetes had the largest ES on MCS (-0.36). CVD moderately affected PCS and MCS (ES -0.34 and -0.27 respectively). Obesity had a negative effect on PCS (ES -0.27). Exercise positively affected PCS and MCS (ES +0.08 and +0.21 (p<0.01) respectively).

Conclusion: Health promotion to reduce the prevalence of chronic diseases is important to improve the quality of life in Asian populations. Physical activity is an important part of such programs. Awareness of diseases may have greater impacts on mental health than having the disease itself. This has implications for the evaluation of the cost-benefit of screening and labeling of individuals with pre-disease states.