Mothers who have children before age 20 are more likely to develop lung cancer later in life, a new study warns.
Scientists have identified teenage pregnancy as one of the most significant reproductive factors linked to a higher risk of the condition, which kills 35,000 people in the UK every year.
Starting periods at a young age, early menopause and a shortened reproductive period were also on the list.
Researchers from Xiangya Hospital in China examined data from 273,190 people in the UK biobank.
They analyzed the relationships between individual reproductive factors and the risk of developing lung cancer, and also looked at age, smoking habits, body mass index (BMI) and genetic risks.
A total of 1,182 cases of lung cancer were recorded over an average follow-up period of 12 years.
Several factors showed a “significant” association with a higher risk of the disease in women – particularly non-small cell lung cancer (NSCLC).
These included entering puberty before age 11, menopause before age 46, a shorter reproductive period (up to age 32), and having a child before age 20.
A detailed analysis found that some reproductive factors – particularly early menopause, shortened reproductive lifespan and early age at first birth – had a “significantly stronger” association with an increased risk of lung cancer.
The lead researcher Dr. Yi Zhang from Central South University said: “These results are of utmost importance to our understanding of the potential risk factors for lung cancer in women.”
She added: “Early menarche, early menopause and shortened reproductive lifespan are associated with a higher risk of developing lung cancer, particularly non-small cell lung cancer, in subpopulations with specific genetic risk and certain lifestyle choices.”
Dr. Zhang said the research highlights the importance of screening multiple reproductive factors in identifying potential lung cancer risk in women.
The results were presented at the International Association for the Study of Lung Cancer World Conference 2023 in Singapore.
According to Cancer Research UK, around 85 percent of lung cancers are NSCLC.
The three main types are adenocarcinoma, squamous cell carcinoma and large cell carcinoma.