> ## Content Index
> Fetch the complete content index at: https://www.foodconsumer.org/llms.txt
> Use this file to discover other available public pages before exploring further.

# Reproductive factors linked to lung cancer risk
- URL: https://www.foodconsumer.org/reproductive_factors_lung_cancer_risk_0909120344/
- Published: 2012-09-09T16:43:00.000Z
- Updated: 2026-09-22T16:18:11.000Z
- Description: In a Singapore study of 702 Chinese women with lung cancer and 1,578 hospital controls, reproductive factors tracked with risk among never-smokers: menstrual cycles longer than 30 days were linked to 50 percent lower risk, and a first birth before 30 to 47 percent lower.
- Author: Food Consumer
- Tags: Disease, Health News, #vivvo-import

By David Liu, PHD

Sunday Sept 9, 2012 ([foodconsumer.org](http://www.foodconsumer.org/)) -- If you are a woman and you face a higher risk for breast cancer, then you may also be at high risk for lung cancer, according to a study recently published in American Journal of Epidemiology.

Wei-Yen Lim of National University of Singapore in Singapore, Singapore and colleagues conducted the study and found many reproductive factors that are linked to high risk of breast cancer were also associated with high risk for lung cancer.

The study involved 702 Singapore Chinese female lung cancer cases and 1,578 hospital controls of whom 433 cases and 1375 controls were never smokers.

Among never smokers, giving birth to one child was linked to 8 percent reduced risk for lung cancer, compared to giving no birth. Having a menstrual cycle length of longer than 30 days were 50 percent less likely to be diagnosed with lung cancer, compared to having a menstrual cycle length of less than 30 days. Giving birth to first child at an age younger than 30 years was linked to 47% reduced risk for lung cancer, compared to those having the first birth at an age older than 40 years.

Among smokers, parity was inversely associated with lung cancer, but other reproductive factors were not associated with the risk. This could mean that other factors are overshadowed by the risk of smoking.

The researchers also analysed the association between five estrogen pathway gene polymorphisms and found the COMT rs4680 A allele was positively associated with lung cancer in never smokers. Those with this variant were 46% more likely to develop lung cancer. But other polymorphisms were not associated with the risk.