Association between depressive symptoms and objectively measured daily step count in individuals at high risk of cardiovascular disease in South London, UK: a cross-sectional study

OBJECTIVES: Depressive symptoms are common but rarely considered a risk factor for unhealthy lifestyles associated with cardiovascular disease (CVD). This study investigates whether depressive symptoms are associated with reduced physical activity (PA) in individuals at high risk of developing CVD. DESIGN: Secondary analysis of the cross-sectional baseline data from a randomised controlled trial of an intensive lifestyle intervention. SETTING: 135 primary care practices in South London, UK. PARTICIPANTS: 1742 adults, 49–74 years, 86% male at high (≥20%) risk of developing CVD in the next 10 years as defined via QRISK2 score. OUTCOME MEASURES: The main explanatory variable was depressive symptoms measured via the Patient Health Questionnaire-9 (PHQ-9). The main outcome was daily step count measured with an accelerometer (ActiGraph GT3X) stratified by weekdays and weekend days. RESULTS: The median daily step count of the total sample was 6151 (IQR 3510) with significant differences (P<0.001) in mean daily step count between participants with low (PHQ-9 score: 0–4), mild (PHQ-9 score: 5–9) and moderate to severe depressive symptoms (PHQ-9 score: ≥10). Controlling for age, gender, ethnicity, education level, body mass index (BMI), smoking, consumption of alcohol, day of the week and season, individuals with mild depressive symptoms and those with moderate to severe depressive symptoms walked 13.3% (95% CI 18.8% to 7.9%) and 15.6% (95% CI 23.7% to 6.5%) less than non-depressed individuals, respectively. Furthermore, male gender, white ethnicity, higher education level, lower BMI, non-smoking, moderate alcohol intake, weekdays and summer season were independently associated with higher step count. CONCLUSIONS: People at high risk of CVD with depressive symptoms have lower levels of PA. TRIAL REGISTRATION: ISRCTN84864870; Pre-results.