A total of 206 women and 143 men were diagnosed with pancreatic cancer during 2
077 person-years of follow-up. Of these 349 persons, 333 (96%) died of the disease. At baseline, 9.2% of the women (16.4% by 1996) and 3.7% of the men (7.1% by 1996) reported gallstones or a history of cholecystectomy. Characteristics of the study population are described in .
Age and age-standardizeda characteristics by exposure status (gallstones and/or cholecystectomy) among women in the NHS and men in the HPFS
In our primary analysis we excluded participants who reported a history of cholecystectomy or gallstones from the proceeding 2 years of analysis, which left 170 women and 127 men with a diagnosis of pancreatic cancer. Of these, women with a history of gallstones or a cholecystectomy experienced a modest elevation in risk for pancreatic cancer (age-adjusted RR=1.47, 95% CI, 1.00–2.16), whereas men with such a history did not experience an obvious increase in risk (). Among men and women combined, the age-adjusted RR was 1.31 (95% CI, 0.93–1.83). However, after adjusting for other factors, including body mass index and physical activity, the RR was 1.11 (95% CI, 0.78–1.56). Adjustment for postmenopausal hormone use and parity among women did not substantially alter our estimates (data not shown).
Multivariate RRs in the analyses that included all 349 diagnosed pancreatic cancer case subjects were not substantially different from the primary analyses for women (RR=1.16, 95% CI, 0.81–1.66), men (RR=0.96, 95% CI, 0.52–1.75), or women and men combined (RR=1.10, 95% CI, 0.81–1.50).
We examined the relation between time since cholecystectomy and risk of pancreatic cancer. Among individuals with a cholecystectomy 10 or fewer years in the past, the multivariate RR for pancreatic cancer was 1.12 (95% CI, 0.66–1.89), whereas for more than 10 years in the past, the RR was 1.13 (95% CI, 0.76–1.68). For cholecystectomy more than 20 years in the past, the RR was 0.88 (95% CI, 0.49–1.59). These findings were not materially different when we examined time interval since cholecystectomy or a diagnosis of gallstones; for individuals with a history of either cholecystectomy or gallstones more than 10 years previously, the RR for pancreatic cancer was 1.16 (95% CI, 0.79–1.70).