Table 4. Frequency of alcohol drinking on HIV-1 incidence by age group.

Characteristic	IRR (95% CI) by Age group
	30+	25–29	18–24
Alcohol drinking
No	1 (Ref)	1 (Ref)	1 (Ref)
Yes	2.45	6.18	3.03
	(0.79–7.61), p = 0.12	(1.41–27.0), p = 0.016	(0.96–9.51), p = 0.058
Frequency of alcohol drinking
No	1 (Ref)	1 (Ref)	1 (Ref)
Occasional	1.54	4.02	2.10
	(0.34–6.89), p = 0.57	(0.78–20.7), p = 0.096	(0.53–8.41), p = 0.293
Regular	3.06	8.44	4.04
	(0.94–9.93), p = 0.063	(1.85–38.5), p = 0.006	(1.18–13.8), p = 0.026