“…Smoking is associated with lower serum and urinary estrogen levels in some (MacMahon et al, 1982; Westhoff et al, 1996), but not all (Longcope and Johnston, 1988;Zumoff et al, 1990;Daniel et al, 1992), studies. Alcohol consumption is associated with higher endogenous levels of estradiol (E 2 ) and estrone (Katsouyami et al, 1991;Reichman et al, 1993;Hankinson et al, 1995), but other studies show no such associations (Cauley et al, 1989;London et al, 1991;Dorgan et al, 1994;Newcomb et al, 1995). Coffee and caffeine consumption are associated with increased levels of early follicular phase E 2 , independent of alcohol or tobacco use (Lucero et al, 2001), and may enhance sex steroid production (Leonard et al, 1987).…”