Table 3.

Mean change in depressive symptom severity score per 1-point increase in loneliness score, using repeated measures of depressive symptoms from waves three to eight

	Change in depressive symptom severity score (95% CI)	p value
Model one: univariable association	0·38 (0·35–0·41)	<0·0001
Model two: model one plus continuous linear time variable	0·38 (0·35–0·41)	<0·0001
Model three: model two plus continuous quadratic time variable*	0·38 (0·35–0·41)	<0·0001
Model four: model two adjusted for social experiences related to loneliness†	0·36 (0·33–0·40)	<0·0001
Model five: model four adjusted for polygenic risk scores‡	0·36 (0·32–0·39)	<0·0001
Model six: model five adjusted for sociodemographic factors§	0·33 (0·29–0·36)	<0·0001
Model seven: model six adjusted for health indicators¶	0·29 (0·26–0·32)	<0·0001
Model eight: model seven adjusted for depressive symptoms at baseline‖	0·16 (0·13–0·19)	<0·0001

^*Time squared was subsequently excluded from models because of no evidence of departure from linearity.

^†Social network size, social contact frequency, participation in social groups, and perceived social support.

^‡Polygenic risk scores for depressive symptoms and loneliness.

^§Age, sex, ethnicity, marital status, level of education, employment status, and wealth.

^¶Long-term physical illness, mobility impairment, pain, body-mass index, waist circumference, and cognitive function.

^‖Interactions between loneliness and time and loneliness and time squared were added to model eight; results for interaction terms are reported in the text.