Associations of daytime napping and nighttime sleep quality with depressive symptoms in older Chinese: the Guangzhou biobank cohort study

Poor sleep quality has been linked to depression in older adults, but results of the association between daytime napping and depression remains limited and conflicting. Moreover, whether the association of daytime napping with depression varies by nighttime sleep quality is unclear. Hence, we examined the associations of daytime napping and nighttime sleep quality with depressive symptoms in older Chinese. A total of 16,786 participants aged ≥50 from the Guangzhou Biobank Cohort Study second-round examination (2008–2012) were included in this cross-sectional study. Geriatric Depression Scale (GDS-15), Pittsburgh Sleep Quality Index (PSQI), napping and demographic data were collected by face-to-face interview using a computerized questionnaire. Logistic regression was used to calculate odds ratio (OR) of depressive symptoms for napping and sleep quality. The prevalence of depressive symptoms (GDS score > 5) and poor global sleep quality (PSQI score ≥ 6) was 5.3 and 31.9