Table 1.

The basic characteristics of study participants.

	PHQ-9 score	Self-reported depression	Age at first episode of depression	Depression possibly related to childbirth
Participants	84,805	85,073	43,664	26,696
Females, n (%)	45,866 (54.1)	46,457 (54.6)	27,358 (62.7)	26,696 (100.0)
Age (years)	56.23 ± 7.58	56.44 ± 7.62	55.63 ± 7.55	55.44 ± 7.45
Alcohol frequency weekly	10.02 ± 9.17	10.02 ± 9.88	9.76 ± 9.18	7.92 ± 7.05
Smoking frequency daily	5.68 ± 9.86	6.14 ± 10.23	6.01 ± 10.03	4.94 ± 8.60
Townsend deprivation index	−1.97 ± 2.67	−1.79 ± 2.77	−1.82 ± 2.74	−1.88 ± 2.69

Notes: PHQ: Patient Health Questionnaire. Age, Alcohol frequency weekly, Smoking frequency daily and Townsend deprivation index were described as Mean ± standard deviation.