Environmental exposures and their genetic or environmental contribution to depression and fatigue: a twin study in Sri Lanka

Table 5 Aetiology of the association between depression and measured environments

Measured environment	Sex group	Time period	Abnormal fatigue (past month)
			MZ differences OR (95% CI) 'E'	Interaction: familiality¹ X zygosity, z score (p) 'A'	Familiality¹ OR (95% CI)
Early school leaving	Men	Prior to age 16 in 95% of cases	3.52 (1.79-6.93)	1.31 (0.189)	1.14 (0.81-1.60)
	Women		1.28 (0.68-2.39)	0.54 (0.586)	1.54 (1.18-2.00)
	All		1.98 (1.25-3.13)	1.22 (0.223)	1.37 (1.11-1.68)
Standard of Living	Men	Current	1.46 (0.77-2.76)	0.41 (0.682)	1.71 (1.21-2.40)
	Women		1.07 (0.65-1.77)	1.15 (0.248)	1.79 (1.36-2.36)
	All		1.19 (0.80-1.77)	0.65 (0.516)	1.77 (1.43-2.20)
Life Events	Men	Past year	1.46 (1.05-2.02)	1.07 (0.286)	1.58 (1.29-1.93)
	Women		1.97 (1.49-2.61)	0.40 (0.690)	1.39 (1.16-1.67)
	All		1.74 (1.41-2.14)	0.44 (0.663)	1.47 (1.28-1.68)
Parental care (continuous)	Men	Prior to age 17 (retrospective)	1.00 (0.88-1.13)	0.17 (0.861)	1.58 (1.29-1.93)
	Women		0.94 (0.87-1.02)	0.76 (0.446)	0.91 (0.87-0.95)

Logistic regressions examining MZ differences ('E') (predicting within-pair difference in fatigue from within-pair differences in environments), and familiality ('A' and 'C') (predicting fatigue from co-twin's environmental experiences, in both MZ and DZ pairs)
¹Familiality: all twins except DZOS

ISSN: 1471-244X