Smoking, early menopause and lung cancer link

Encouraging young women to quit smoking has taken on added importance after University of Queensland research showed associations between smoking, early menopause and lung cancer.

Professor Gita Mishra and colleagues from UQ’s School of Public Health found women who experienced early menopause at age 45 or younger had an increased risk of lung cancer, although the risk was primarily among smokers.

“Menstrual and reproductive factors have previously been associated with lung cancer risk, but the association with age at menopause was inconsistent,” Professor Mishra said.

“Early menopause has been linked with many adverse health outcomes in later life, including cardiovascular disease, type 2 diabetes and early death, and now lung cancer, especially among smokers.

“As smoking is a main risk factor for both early menopause and lung cancer, it represents a potential target for early preventative interventions, especially to help females in early adulthood quit.”

In 2018 lung cancer contributed to 13.8 per cent of deaths due to cancer in females, second only to breast cancer.

While men have historically displayed a higher incidence of lung cancer, over the past two decades this trend has reversed, and the statistics are not fully explained by smoking behaviours.

“Given the same level of lifelong exposure to cigarettes, female smokers appear to have increased susceptibility to develop lung cancer, compared to male smokers,” Professor Mishra said.

“Women who have never smoked are still twice as likely to develop lung cancer as men who have never smoked.

“Understanding the sex-specific risk factors and how exposure to oestrogen relates to lung cancer for women is of the utmost importance.”

Professor Mishra undertook the research with UQ Faculty of Medicine colleagues Dr Hsin-Fang Chung and PhD candidate Mr Dereje G Gete.

Dr Chung said that there were also associations between late menopause (age 55 or older) and lung cancer risk which warranted further investigation.

“Interestingly though, that was mainly among non-smokers, indicating greater exposure to estrogen may play a role in lung cancer development among non-smokers,” Dr Chung said.

“That observation needs to be confirmed in larger cohort studies now, as the only associations have been in four case-control studies.

“From here, further research is required to investigate underlying molecular mechanisms, especially the interaction between tobacco carcinogens and sex hormones in lung cancer development.”

Data for the UQ research was gathered by combining results from 17 previous studies.

The outcomes have been published in Maturitis (DOI: 10.1016/j.maturitas.2021.07.010).