Men have greater cancer risk because of biology NOT because they drink and smoke more, study claims

Men drink and smoke more than women — but that is not the reason they have a higher cancer risk.

A major study suggests biological differences are the real reason behind the disparity between sexes. 

Understanding these differences could help to improve prevention and treatment, researchers say. 

The study looked at 300,000 middle-aged and older Americans who did not have cancer over 15 years.

Men were more than twice as likely to develop the disease compared to women — even when lifestyle factors were ruled out.

‘This suggests that there are intrinsic biological differences between men and women that affect susceptibility to cancer,’ said lead researcher Dr Sarah Jackson, an epidemiologist at the National Cancer Institute.

The observational study did not look at what these differences are. 

Some 182,000 women are diagnosed with cancer in the UK every year, rising to 193,000 among men.

In the US, 970,000 men and 928,000 women have cancer confirmed annually. 

Researchers from the NCI examined the rates of 21 types of cancers in 171,274 men and 122,826 women.

Participants were aged 50 to 71 and their records were monitored between 1995 and 2011.

The findings, published in the journal CANCER, show 17,951 cancers were detected among men, while just 8,742 were diagnosed among women.

Rates of thyroid and gallbladder cancer were higher among women, but the prevalence of all other cancers were higher among men. 

Men were 11-times more likely to develop oesophageal cancer and four times more at risk of stomach or throat cancer.

They also had a three times greater chance of being diagnosed with bladder cancer.

But after accounting for cancer risk factors, such as smoking, alcohol intake and exposure to toxic chemicals, men were still more likely to develop cancer.

Scientists have previously pointed to higher rates of smoking, alcohol consumption and exposure to carcinogens — such as asbestos — due to factory work. 

They also said men may be less likely to seek medical advice.

But the results suggest that biological differences between the sexes — such as in physiology, immune system and genes — play a ‘major role’ in cancer susceptibility.

Scientists have previously found that women have an extra copy of genes that protect against cancer than men. 

Study leader Dr Sarah Jackson, an epidemiologist at the National Cancer Institute, said: ‘Our results show that there are differences in cancer incidence that are not explained by environmental exposures alone.’

In an editorial accompanying the study, researchers at Washington University called for sex to be taken into account by medics when determining someone’s risk of cancer, screening and treatment.

This approach could mitigate and ‘may ultimately eradicate’ sex disparities in cancer, they said.