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

Table 2 Aetiology of measured environments - univariate ACE models

Measured environment	Sex group	Variance Components			Fit
		A	C	E	Δ χ²	Δ df	P
Early school leaving	Male	0.53 (0.15-0.74)	0.36 (0.18-0.71)	0.10 (0.06-0.18)	1.907¹	1	0.167
	Female	0.35 (0.13-0.65)	0.57 (0.28-0.77)	0.08 (0.04-0.13)
	Combined	0.45 (0.31-0.60)	0.46 (0.32-0.59)	0.09 (0.06-0.13)	1.766 ²	2	0.413
Standard of living	Male	0.16 (0.00-0.44)	0.60 (0.36-0.79)	0.23 (0.15-0.32)	0.398¹	1	0.528
	Female	0.22 (0.00-0.47)	0.55 (0.34-0.77)	0.22 (0.15-0.32)
	Combined	0.20 (0.00-0.40)	0.57 (0.41-0.73)	0.23 (0.17-0.30)	0.095 ²	2	0.953
Life events	Male	0.34 (0.00-0.59)	0.13 (0.00-0.45)	0.53 (0.41-0.66)	0.441¹	1	0.507
	Female	0.45 (0.14-0.57)	0.02 (0.00-0.27)	0.53 (0.42-0.65)
	Combined	0.44 (0.20-0.55)	0.03 (0.00-0.22)	0.53 (0.45-0.62)	0.457 ²	2	0.796
Parental care (continuous)	Male	0.36 (0.15-0.59)	0.28 (0.07-0.47)	0.36 (0.31-0.42)	14.020³ 4.641⁴	8 1	0.081 0.031
	Female	0.12 (0.003-0.30)	0.45 (0.29-0.57)	0.43 (0.37-0.48)
	Combined	0.22 (0.09-0.36)	0.39 (0.25-0.50)	0.40 (0.36-0.44)	3.829 ²	2 ²	0.147

Best fitting model shown in bold
¹Fit of ACE model to fully saturated model
²Fit of model dropping quantitative sex differences compared to models with A, C and E parameters estimated separately for males and females.
³Fit of scalar ACE model to fully saturated model
⁴Fit of model dropping qualitative sex differences

ISSN: 1471-244X