Parity and other reproductive factors and risk of adenomatous polyps of the distal colorectum (United States)

Age at menarche and risk of colorectal adenoma

BACKGROUND/AIMS

Limited data are available regarding the association between age at menarche and the risk of colorectal adenoma. Therefore, we aimed to evaluate the relationship between reproductive factors including age at menarche and the risk of colorectal adenoma.

METHODS

A cross-sectional study was performed on asymptomatic female subjects who underwent colonoscopy between 2010 and 2014 as part of a comprehensive health screening program in Korea. The association between reproductive factors including age at menarche and the presence of adenomas was assessed using multivariate logistic regression analysis.

RESULTS

Among 32,620 asymptomatic female subjects, the proportion of patients with menarche at 10 to 11, 12 to 13, 14 to 15, 16 to 17, and 18 to 19 years of age was 4.1%, 31.7%, 45.4%, 14.9%, and 4.0%, respectively. Age at menarche was not significantly associated with the risk of any adenoma (adjusted odds ratio [AOR], 0.99; 95% confidence interval [CI], 0.97 to 1.02; p = 0.500) or advanced adenoma (AOR, 0.98; 95% CI, 0.91 to 1.04; p = 0.468) after adjusting for confounding factors. Age at menarche was not significantly associated with the risk of adenoma even among similar age groups. In addition, parity, use of female hormones, and menopause were not associated with the risk of adenoma.

CONCLUSION

Age at menarche, parity, use of female hormones, and menopause were not significantly associated with the risk of colorectal adenoma. Our findings indicate that reproductive factors including age at menarche do not affect the development of colorectal adenoma.

Hormone replacement therapies, oral contraceptives, reproductive factors and colorectal adenoma risk: a systematic review and dose-response meta-analysis of observational studies

AIM

The association between the use of oral contraceptives and hormone replacement therapy (HRT) or other reproductive factors and the risk of colorectal adenoma (CRA) remains controversial. Our study aimed to review the evidence by conducting a dose-response meta-analysis to investigate this association.

METHODS

We searched PubMed and Embase databases for relevant studies published until May 2017. Traditional and dose-response meta-analyses were conducted. Sensitivity analysis was performed to evaluate the robustness of the results. Cumulative meta-analysis was used to assess the risk of different oral contraceptive formulations or generations.

RESULTS

A total of 19 observational studies, with 21 923 CRA cases and 1 030 711 participants, were included in the meta-analysis. Ever HRT use showed a potential inverse association with CRA risk [relative risk (RR) 0.83, 95% CI 0.70-1.00]. The dose-response meta-analysis further demonstrated that HRT use could reduce CRA risk. Compared with no HRT use, the predicted RRs were 0.82 (95% CI 0.67-0.99), 0.76 (95% CI 0.59-0.98) and 0.77 (95% CI 0.62-0.96) for 3, 6 and 9 years of HRT use, respectively. All other factors were not statistically significantly associated with CRA risk.

CONCLUSIONS

This study indicated that only HRT use might reduce the risk of developing CRA. Any advice regarding HRT use to prevent CRA should be tailored to the individual risks and potential benefits. Large, well-designed prospective studies with long-term follow-up are required to further clarify the aetiology of CRA.

Reproductive factors and risk of colorectal polyps in a colonoscopy-based study in western Washington State

BACKGROUND

Oral contraceptives (OC) are associated with a decreased risk of colorectal cancers; however, a recent study reported an increased risk of small colorectal adenomas associated with OC use. To determine if these results were replicable in a different study population, we investigated the relationship between OC use and other reproductive factors and risk of colorectal polyps in a case-control study in western Washington.

METHODS

Study participants were 24-79-year-old female enrollees at an integrated health care system in western Washington who were diagnosed as having adenomas (n = 299), serrated polyps (n = 337), both types of polyps (n = 105) or as polyp-free controls (n = 615) through an index colonoscopy and completed a structured interview to collect reproductive history information. Multivariable polytomous logistic regression was used to compare case groups to controls and to each other; odds ratios (OR) and 95% confidence intervals were estimated.

RESULTS

There was no association between OC use, duration of use, or recency of use and the risk of either adenomas or serrated polyps [adjusted OR for OC ever use (95% CI) 0.85 (0.58-1.23) and 0.96 (0.66-1.40), respectively], and associations did not differ by lesion severity within the adenoma or serrated pathways. Further, no associations were observed between other reproductive factors and risk of colorectal polyp subtypes.

CONCLUSIONS

Our results suggest that reproductive factors, including OC use, are not associated with early colorectal cancer precursor lesions.

Exogenous Hormone Use: Oral Contraceptives, Postmenopausal Hormone Therapy, and Health Outcomes in the Nurses' Health Study

OBJECTIVES

To review the contribution of the Nurses' Health Study (NHS) to our understanding of the complex relationship between exogenous hormones and health outcomes in women.

METHODS

We performed a narrative review of the publications of the NHS and NHS II from 1976 to 2016.

RESULTS

Oral contraceptive and postmenopausal hormone use were studied in relation to major health outcomes, including cardiovascular disease and cancer. Current or recent oral contraceptive use is associated with a higher risk of cardiovascular disease (mainly among smokers), melanoma, and breast cancer, and a lower risk of colorectal and ovarian cancer. Although hormone therapy is not indicated primarily for chronic disease prevention, findings from the NHS and a recent analysis of the Women's Health Initiative indicate that younger women who are closer to menopause onset have a more favorable risk-benefit profile than do older women from use of hormone therapy for relief of vasomotor symptoms.

CONCLUSIONS

With updated information on hormone use, lifestyle factors, and other variables, the NHS and NHS II continue to contribute to our understanding of the complex relationship between exogenous hormones and health outcomes in women.

A prospective study of oral contraceptive use and colorectal adenomas

PURPOSE

The influence of reproductive factors on colorectal cancer, including oral contraceptive (OC) use, has been examined, but less research is available on OC use and adenomas.

METHODS

Participants of the Nurses' Health Study who had a lower bowel endoscopy between 1986 (when endoscopies were first assessed) and 2008 were included in this study. Multivariable logistic regression models for clustered data were used to estimate odds ratios and 95 % confidence intervals [OR (95 % CIs)].

RESULTS

Among 73,058 participants, 51 % (n = 37,382) reported ever using OCs. Ever OC use was associated with a slight increase in non-advanced adenomas [OR 1.11, 95 % CI (1.02, 1.21)] but not with any other endpoints. Duration of OC use was not associated with adenomas, but longer times since last OC use were associated with increased odds of adenomas [e.g., compared to never use, 15+ years since last use: OR 1.17 (1.07, 1.27)]. Shorter times since last OC use were inversely associated [e.g., ≤4 years since last use: OR 0.74 (0.65, 0.84)].

CONCLUSIONS

We observed a modest borderline increase in risk of colorectal adenomas with any prior OC use. Additionally, more recent OC use may decrease risk, while exposure in the distant past may modestly increase risk of adenomas.

Reproductive history and risk of colorectal adenocarcinoma

BACKGROUND

Sex hormones may be associated with colorectal adenocarcinoma, although the association of pregnancy history and risk of colorectal cancer is not consistent.

METHODS

We conducted a population-based nested case-control study of persons born between 1932 and 2008 who are in the Swedish Multi-Generation Register. In total, 12,915 women and 15,519 men with colorectal adenocarcinoma were identified during follow-up in the Swedish Cancer Register; 10 age- and sex-matched controls were selected for each case. Number of children and age at first and last birth were analyzed in relation to the risk of colorectal adenocarcinoma, using conditional logistic regression, to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Compared with women without children, women with 1 or 2 children had an OR of 1.02 (95% CI = 0.93-1.13) of developing adenocarcinoma in the proximal colon; those with 3 or 4 children, 1.18 (1.06-1.32); and those with ≥5 children, 1.30 (1.05-1.61) (test for trend P < 0.01). The corresponding associations in men were 0.92 (0.84-1.00), 1.02 (0.92-1.13), and 0.97 (0.78-1.20), respectively (test for trend P = 0.13).

CONCLUSIONS

Higher parity in women was associated with the risk of adenocarcinoma of the proximal colon, although not the distal colon or rectum. A similar risk with family size was not seen for fathers. Still, the influence of lifestyle factors cannot be ruled out.

Insulin resistance, central obesity, and risk of colorectal adenomas

BACKGROUND

Increasing evidence supports insulin resistance (IR) as the underpinning of the obesity-colorectal neoplasia link. The homeostasis model assessment-IR (HOMA-IR) is a widely accepted index of evolving hyperinsulinemia and early IR. Studies of the relation between HOMA-IR and colorectal adenomas are limited. Therefore, the authors sought to determine the associations of HOMA-IR and central obesity (waist to hip ratio [WHR]) with risk of colorectal adenomas in a screening colonoscopy-based study.

METHODS

The authors collected lifestyle information and fasting blood samples from 1222 participants (320 incident adenoma cases and 902 without adenomas) before their screening colonoscopies. Unconditional logistic regression models were used to assess risk associations.

RESULTS

In multivariate analysis of participants (n = 1093) reporting no antidiabetic medication use, those in the top quartile of WHR were twice as likely (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.33-3.57; P-trend = .003) and those in the top quartile of HOMA-IR were 63% more likely (OR, 1.63; 95% CI, 1.09-2.44; P-trend = .01) to have adenomas compared with those in the bottom quartiles. Stratified analysis revealed a statistically significant interaction between HOMA-IR and sex (P-interaction = .04), with the association largely limited to men; compared with those in the bottom tertile, men in the top tertile of HOMA-IR were twice more likely to have adenomas (OR, 2.11; 95% CI, 1.18-3.78; P-trend = .01).

CONCLUSIONS

The results support central obesity and insulin resistance, particularly in men, as important risk factors for the development of early colorectal neoplasia.

Oral contraceptives, reproductive history and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Oral contraceptive use and reproductive factors may initiate long-term changes to the hormonal milieu and thereby, possibly influence colorectal cancer risk.

METHODS

We examined the association of hormonal and reproductive factors with risk of colorectal cancer among 337,802 women in the European Prospective Investigation into Cancer and Nutrition, of whom 1878 developed colorectal cancer.

RESULTS

After stratification for center and age, and adjustment for body mass index, smoking, diabetes mellitus, physical activity and alcohol consumption, ever use of oral contraceptives was marginally inversely associated with colorectal cancer risk (hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.83-1.02), although this association was stronger among post-menopausal women (HR, 0.84; 95% CI: 0.74-0.95). Duration of oral contraceptive use and reproductive factors, including age at menarche, age at menopause, type of menopause, ever having an abortion, parity, age at first full-term pregnancy and breastfeeding, were not associated with colorectal cancer risk.

CONCLUSION

Our findings provide limited support for a potential inverse association between oral contraceptives and colorectal cancer risk.

Hormone replacement therapy, reproductive history, and colorectal adenomas: data from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial (United States)

OBJECTIVE

Findings from some epidemiologic studies of colorectal cancer and adenoma suggest that the protective effect of post-menopausal hormone replacement therapy (HRT) may differ across categories of age and body mass index (BMI). We conducted an analysis of women participating in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial to investigate the relationship between HRT use and prevalent adenoma, both overall and across different population subgroups.

METHODS

Women aged 55-74 were randomized to screening by flexible sigmoidoscopy at ten PLCO screening centers between September 1993 and September 2001. We identified 1468 women with at least one left-sided adenoma and 19,203 without adenoma or colorectal cancer. Information about HRT and reproductive factors was obtained from a self-administered questionnaire.

RESULTS

Compared to never use of HRT, current use was associated with a decreased prevalence of left-sided adenoma (odds ratio (OR) 0.85; 95% confidence interval (CI) 0.75-0.97). We found no evidence of dose-response with increasing duration of use for current or former users. The association with current HRT use was stronger among women aged 65+ (OR 0.69; 95% CI 0.56-0.84), with a BMI<30 (OR 0.82; 95% CI 0.71-0.95) and who regularly use aspirin or ibuprofen (OR 0.77; 95% CI 0.65-0.91). Other reproductive factors were not significantly associated with adenoma prevalence.

CONCLUSIONS

Our findings suggest that current HRT use may protect against colorectal adenoma, and that this protective effect is short-lived following cessation of use.

Association between physical activity, fiber intake, and other lifestyle variables and constipation in a study of women

Because the risk factors for constipation in the general population are poorly defined, we examined the association between age, body mass index, and selected lifestyle and dietary factors with the prevalence of constipation in the Nurses' Health Study.A total of 62,036 women, aged 36-61 yr and free of cancer, responded to mailed questionnaires in 1980 and 1982, which assessed bowel movement frequency, dietary, and lifestyle factors. Constipation was defined as two or fewer bowel movements weekly.A total of 3327 women (5.4%) were classified as having constipation. Age and body mass index were inversely associated with constipation (p for trend < 0.0001). In multivariate analysis, women who reported daily physical activity had a lower prevalence of constipation (prevalence ratio [PR] = 0.56, 95% CI = 0.44-0.70). Women in the highest quintile of dietary fiber intake (median intake 20 g/day) were less likely to experience constipation (PR = 0.64, 95% CI = 0.57-0.73) than women in the lowest quintile (median intake 7 g/day). The PR for constipation for women who both reported daily physical activity and were in the highest quintile of fiber intake was 0.32 (95% CI = 0.20-0.54) compared with those with physical activity less than once weekly and those who were in the lowest quintile of fiber intake. Higher frequency of aspirin intake was associated with an increasing prevalence of constipation (PR = 1.38, 95% CI = 1.17-1.62). Current smoking and alcohol use were inversely associated with constipation. Our data suggest that moderate physical activity and increasing fiber intake are associated with substantial reduction in the prevalence of constipation in women.

Risk of colorectal cancer after breast cancer

BACKGROUND

History of breast cancer has been reported as a risk factor for colorectal cancer in women. In view of the ambiguous nature of existing evidence and the growing interest in targeted colorectal cancer prevention, we sought to quantify this risk.

METHODS

We used the Surveillance Epidemiology and End Results (SEER) database to estimate risk of colorectal cancer after breast-cancer diagnosis in women with first incident breast cancer between 1974 and 1995. Observed colon and rectal cancer risk was compared with that expected in the general population. We stratified comparisons by age at breast-cancer diagnosis, stage of cancer, ethnic origin of patient, and follow-up time.

FINDINGS

Overall, women with previous breast cancer were 5% less likely (95% CI 1-9) to develop colon and 13% less likely (6-19) to develop rectal cancer than women in the general population. Stratified analyses suggested that the risk reductions observed for colon and rectal cancer were most pronounced for women with breast cancer diagnosed after age 65 years, in white women, women with local stage breast cancer, and women diagnosed in the later study years (1990-94).

INTERPRETATIONS

Breast cancer does not increase subsequent colorectal cancer risk, and reduced risk was seen for certain subgroups of women. Because no biologically plausible endogenous protective factor has been identified, we suggest that reduced risk could stem from an accumulation of exposures that increase breast-cancer frequency but protect against colorectal cancer.

Oral contraceptives and colorectal tumors. A review of epidemiologic studies

Over the last two decades, the mortality rates of colorectal cancer in many developed countries have declined in women but not in men. One of the explanations of this difference between the genders may be the favorable influence of the spread of exogenous female hormone use (i.e., oral contraceptives [OC] and hormone replacement therapy) Reduced risk in ever-users of OC was found in three of four cohort studies available on this topic, and was significant in the one based on colorectal cancer mortality. The fourth one showed no difference. Of 11 case-control studies (or groups of studies), none showed significantly elevated risk. Five reported lowered colorectal cancer risk among ever-users, with a significant inverse association in the largest investigation available. Recent OC use, more than long duration use, seemed to be related to some risk reduction. One cohort study and three case-control investigations suggested that OC use was not related to the risk of colorectal adenomatous polyps. Thus, at present, it seems that OC use does not increase and may even have a favorable effect on either incidence or mortality of colorectal cancer.