Related Experiment Video
Updated: Aug 25, 2026

Competing-Risk Nomogram for Predicting Cancer-Specific Survival in Multiple Primary Colorectal Cancer Patients after Surgery
Published on: September 27, 2024
A prospective study on the possible association between having children and colon cancer risk: findings from the JACC
Koji Tamakoshi1, Kenji Wakai, Masayo Kojima
1Department of Public Health/Health Information Dynamics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan. tamako@med.nagoya-u.ac.jp
Abstract:
If having children is regarded as an exposure in life, its effect on a host could be considered as being due to female sex hormones associated with pregnancy in women and some lifestyle factors associated with large families in both men and women. To explore the roles of having children in the etiology of colon cancer, we examined 36,629 women and 24,877 men aged 40-79 years who completed a questionnaire on the number of children and other lifestyle factors from 1988 to 1990 in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. During 291,080 and 200,648 person-years of follow-up, we documented 198 female and 202 male incident colon cancers, respectively. After adjusting for some factors known or suspected to modify the risk of colon cancer, compared with the women with no children, the multivariate-adjusted relative risks of colon cancer were 0.74 (95% confidence interval [CI]: 0.30-1.84) for one child, 1.00 (95% CI: 0.46-2.20) for two, 0.70 (95% CI: 0.31-1.55) for three, and 0.59 (95% CI: 0.26-1.33) for four or more. The risk of colon cancer showed a significantly monotonic decrease with increasing number of children (P value for trend = 0.047). There was no association between the number of children and colon cancer risk among men. From these prospective data, having children may reduce risk of colon cancer among women, but not among men, suggesting that modifications of hormone profiles secondary to pregnancies may influence female colon cancer risk.
Related Concept Videos
Observational Studies
There are three types of observational studies โ Prospective, retrospective, and cross-sectional.
Prospective Study
Prospective studies, also known as longitudinal or cohort studies, are carried out by collecting future data from groups sharing similar characteristics. One example of...
Cancer Prevention
Some...
Cancer Prevention
Some...
Longitudinal Research
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Cancer Survival Analysis
