New Delhi

Non-vegetarian diet, poor sleep quality and obesity are associated with an increased risk of breast cancer among Indian women, with cases projected to rise by about 5.6 per cent annually, adding an estimated 50,000 new cases each year, according to a study by the Indian Council of Medical Research (ICMR).

The study, conducted by ICMR’s National Centre for Disease Informatics and Research (NCDIR), Bengaluru, also found that reproductive timing, hormonal exposure and family history play a significant role in breast cancer risk in India.

Globally, around 2.3 million women were diagnosed with breast cancer in 2022, leading to nearly 6.7 lakh deaths. In India, breast cancer accounted for 2,21,757 cases in 2022, making up 22.8 per cent of all cancers among women.

The findings are based on a systematic review of Indian studies published up to December 22, 2024. Of the 1,871 articles screened, 31 studies met inclusion criteria and were analysed using a random-effects meta-analysis model.

The study reported that menopause after the age of 50 was associated with more than a two-fold increase in breast cancer risk, while early menopause showed a protective effect. Late age at marriage and first childbirth (beyond 30 years) were linked to progressively higher risk. Women with more than two induced abortions had a 1.68 times higher risk compared to those with none.

Anthropometric measures showed abdominal obesity, indicated by a waist-to-hip ratio of 0.85 or higher, had a stronger association with breast cancer than overall body mass index, suggesting fat distribution is a key risk factor among Indian women.

Lifestyle factors also played a major role. A non-vegetarian diet was associated with increased risk, possibly due to higher intake of saturated fats and processed meats that influence estrogen levels. Poor sleep quality and irregular sleep patterns were linked to higher risk, supporting evidence that circadian rhythm disruption and reduced melatonin may contribute to cancer development.

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Alcohol and tobacco use did not show a significant association, which researchers attributed to low consumption levels, underreporting or population-specific factors.