Women with severe sleep apnoea appear to be at an elevated risk of getting cancer, according to a new study published in the European Respiratory Journal.
Ludger Grote, the last author of the study, said: ‘It’s reasonable to assume that sleep apnoea is a risk factor for cancer, or that both conditions have common risk factors, such as [being] overweight. On the other hand, it is less likely that cancer leads to sleep apnoea.’
The research is based on analyses of registry data, collected in the European database ESADA, on a total of some 20,000 adult patients with obstructive sleep apnoea (OSA). About 2 per cent of them also had a cancer diagnosis.
As expected, advanced age was associated with elevated cancer risk, but adjusting the data for age, gender, body mass index (BMI), smoking, and alcohol consumption nevertheless showed a possible link between intermittent hypoxia at night and higher cancer prevalence. The connection applied mainly to women, and was weaker in men. No causal relationship is demonstrated, but the link between nocturnal hypoxia in women and higher cancer risk is still clear.
Grote said: ‘Our results indicate a cancer risk that’s elevated two- to three-fold among women with pronounced sleep apnoea. It’s impossible to say for sure what causes underlie the association between sleep apnoea and cancer, but the indication means we need to study it in more depth.’
Previous studies have shown that, more often than others, people with sleep apnoea have a cancer diagnosis in their medical history. Research in this area is expanding, while the gender aspects have hardly been explored.
‘Above all, the focus has been on the connection with one form of cancer: malignant melanoma. Cancer of the breast or womb may now become a new area. There may be a combined effect of female sex hormones and stress activation, induced by nocturnal hypoxia in sleep apnoea, that can trigger cancer development or a weakening of the body’s immune system.’