Table 4 Crude hazard ratios (HRs) from Cox regression models showing the effect of 5-year birth cohorts on survival time to first sex (data from pooled DHS, Masaka study and Rakai study)

Year of birth	DHS		Masaka		Rakai
Year of birth	Crude HR	p Value	Crude HR	p Value	Crude HR	p Value
Men
1970–4	1		1		1
1975–9	0.99 (0.89 to 1.1)	0.81	1.02 (0.91 to 1.15)	0.7	1.10 (1.03 to 1.17)	0.002
1980–4	0.88 (0.77 to 1.0)	0.059	0.94 (0.83 to 1.06)	0.29	1.59 (1.49 to 1.71)	<0.001
1985–9	0.82 (0.70 to 0.96)	0.011	0.51 (0.44 to 0.59)	<0.001	1.58 (1.42 to 1.76)	<0.001
1990–4	0.8 (0.57 to 1.12)	0.187	0.21 (0.12 to 0.34)	<0.001	–	–
Total	3662		4398		8013

Women
1970–4	1		1		1
1975–9	0.97 (0.92 to 1.03)	0.301	0.93 (0.84 to 1.02)	0.13	0.94 (0.89 to 0.99)	0.016
1980–4	0.82 (0.77 to 0.86)	<0.001	0.84 (0.76 to 0.93)	0.001	1.20 (1.13 to 1.26)	<0.001
1985–9	0.67 (0.62 to 0.73)	<0.001	0.54 (0.48 to 0.61)	<0.001	1.37 (1.27 to 1.49)	<0.001
1990–4	0.44 (0.37 to 0.54)	<0.001	0.27 (0.18 to 0.41)	<0.001	–	–
Total	15734		5328		11707

Restricted to those born on or after 1 January 1970.
DHS, Demographic and Health Survey.