Lin Y, Kikuchi S, Tamakoshi A, Kawamura T, Inaba Y, Kurosawa M, Motohashi Y, Yagyu K, Obata Y, Ishibashi T, JACC Study GroupAssociation of menstrual and reproductive factors with pancreatic cancer risk in women: findings of the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. J Gastroenterol 41: 878-883
The etiology of pancreatic cancer remains largely unknown. We examined the association of pancreatic cancer deaths with menstrual and reproductive factors in a cohort study involving Japanese women.
A total of 63,273 women were followed up for mortality from 1988 to 1999. Information on menstrual and reproductive factors was obtained by a questionnaire survey at baseline. Cox proportional-hazards models were used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for death from pancreatic cancer in relation to menstrual and reproductive factors.
During 631,401 person-years of follow-up, 154 women died from pancreatic cancer. Parity was not significantly associated with the risk of death from pancreatic cancer; the RR was 0.80 (95% CI, 0.31-2.11) for women with six or more births compared with women with zero or one birth. We found no significant overall association with other reproductive factors, including pregnancy, age at first birth, and menopause. The risk appeared to increase with increasing age at menarche; the RR was 1.49 (95% CI, 0.95-2.34) for women who had menarche after 16 years of age compared to those who had menarche before they were 15 years old.
Our prospective data indicate that menstrual and reproductive factors are not associated with the risk of death from pancreatic cancer among Japanese women.
"Two studies2829 were removed for focusing on the number of pregnancy rather than the number of parity. Finally, 10 cohort studies16171819202630313233 and 10 case-control studies14152734353637383940 were eligible for this meta-analysis yielding a combined number of cases of 8205 (Figure 1). Characteristics of the 20 included studies are shown in Table 1. "
[Show abstract][Hide abstract] ABSTRACT: Multiple studies have hypothesized parity is associated with pancreatic cancer risk but obtained conflicting results. We conducted a meta-analysis (including a dose-response approach) of current available epidemiologic studies to investigate the association between parity and risk of pancreatic cancer. Ten cohort studies and ten case-control studies including 8205 cases were eligible for inclusion. The combined RR (relative risk) of pancreatic cancer for the parous vs. nulliparous was 0.91 (95% CI, confidence interval = 0.85-0.97, I(2) = 39.0%, Ph = 0.01). We observed an inverse association between giving birth to two children pancreatic cancer risk with RR of 0.86 (95% CI = 0.80-0.93, I(2) = 8.7%, Ph = 0.36). And no evidence supported there was non-linear (P = 0.33) or linear relationship (P = 0.14) between number of parity and risk of pancreatic cancer. Findings from this meta-analysis indicate that giving birth to two children has the lowest pancreatic cancer risk, mechanism of this protective effect needs further investigation.
[Show abstract][Hide abstract] ABSTRACT: Little is known about the impact of age at menarche on later mortality. In a cohort of 61,319 Norwegian women interviewed in 1956-1959, the authors analyzed associations between age at menarche and all-cause mortality. A total of 36,114 women died during the 37 years of follow-up. An inverse association was found between age at menarche and the all-cause mortality rate (p < 0.001), with an approximately 2.4% (95% confidence interval: 1.6, 3.1) reduced mortality per year increase in age at menarche. The association was stronger in women with an attained age of less than 70 years (3.9% reduction in mortality) than in women aged 80 years and above (1.5%). The inverse association could not be explained by extreme mortality rates in women with very early (10 years) or late (19 years) menarche or by possible confounding variables such as birth cohort, place of residence, occupational category (own or husband's occupation), body mass index, age at first delivery, or parity. Because of lack of data, residual confounding by physical activity or cigarette smoking could not be ruled out. Women with a menarche at age 18 years or later had, however, a slightly higher mortality rate than was predicted by the linear association.
American journal of epidemiology 12/2007; 166(12):1431-7. DOI:10.1093/aje/kwm237 · 5.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A cohort of 63,090 Norwegian women born 1886-1928 was followed more than 38 years, and relations between reproductive factors and risk of pancreatic cancer were explored; 449 cases were recorded at ages 50-89 years. Age at menopause showed a moderately positive association with risk (rate ratio (RR)=1.08 per 2 years delay in menopause; 95% confidence interval (CI)=1.00-1.17). Neither parity nor duration of breastfeeding showed significant associations with risk after adjusting only for demographic factors. With mutual adjustment, however, parity became positively associated (RR=1.13 per delivery; 95% CI=1.05-1.22) while duration of breastfeeding was inversely associated (RR=0.87 per 12 months; 95% CI=0.78-0.97). These associations lessened in magnitude with increasing age, and were essentially absent above age 80 years. Risk was raised among women reporting at least one abortion, but no trend was seen with number of abortions. Together with previous studies, the findings raise questions about the role of chance, but do not exclude hormonal factors related to breastfeeding and pregnancy from affecting pancreatic cancer risk.
British Journal of Cancer 02/2008; 98(1):189-93. DOI:10.1038/sj.bjc.6604095 · 4.84 Impact Factor
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