Table I.

Characteristics of 21 885 women according to tobacco, alcohol and caffeine consumption at the start of follow-up: the Black Women’s Health Study, 1997^a

Characteristic	Cigarette smoking			Alcohol consumption			Caffeine consumption (mg/day)
	Current	Former	Never	Current	Former	Never	<50	150–299	500 +
Number studied	3055	2945	15 885	5367	2684	13 834	9199	3150	1106
Mean of characteristic
Pack-years of cigarette smoking	9.1	5.3	–	3.9	3.9	1.3	1.5	2.9	5.3
Current alcohol consumption (drinks/week) (1995)
Beer	1.5	0.9	0.2	2.0	–	–	0.4	0.6	0.8
Wine	0.7	0.8	0.3	1.7	–	–	0.3	0.5	0.7
Liquor	1.2	0.6	0.2	1.6	–	–	0.3	0.5	0.6
Current alcohol from beer, wine, liquor (g/week) (1995)	43.9	28.5	9.6	67.1	–	–	11.7	20.8	27.2
Caffeine consumption (mg/day) (1995)	212	176	112	179	145	115	22	204	752
Caffeinated coffee (cups/day) (1995)	1.0	0.8	0.4	0.8	0.6	0.4	0.1	0.6	4.2
Energy intake (kilocalories/day) (1995)	1638	1636	1512	1637	1642	1495	1334	1838	1918
Body mass index (kg/m2)	28.2	29.1	27.8	28.0	29.3	27.7	27.4	28.7	29.4
Education (years) (1995)	14.2	14.7	15.1	14.7	14.6	15.1	15.0	14.8	14.7
Age at menarche (years)	12.4	12.3	12.3	12.4	12.3	12.3	12.4	12.3	12.2
Percentage with characteristic
Age (years)
<30	15.3	10.9	33.9	22.7	22.2	31.5	34.3	22.1	12.9
30–39	48.0	43.9	45.0	46.6	43.4	45.2	43.8	46.7	42.8
40 +	36.7	45.2	21.1	30.7	34.4	23.3	21.8	31.2	44.3
Current exposure to environmental tobacco smoke	67.1	18.7	13.7	31.7	27.8	16.5	16.1	26.7	35.8
Parous	62.6	63.2	54.4	55.6	64.5	55.2	54.9	57.9	58.7
Current oral contraceptive use	15.4	21.8	24.7	24.0	19.6	23.6	24.3	21.7	19.4
Pap smear within past 2 years	87.4	91.0	91.0	91.0	89.2	90.5	91.3	89.2	86.7

^aData from 1997 (start of follow-up) unless otherwise noted. Means and percentages (with exception of age) are standardized to the age distribution of women free of uterine leiomyomata at the start of follow-up. Percentages may not add to 100% due to rounding errors.