Having a mental illness increases the risk of developing a physical illness by 10 times in both men and women, the study found. However, women with mental illness tend to develop a physical illness a year earlier than men, according to the study by Dr. Flora Matheson, a scientist in hospital's Centre for Research on Inner City Health.

Women were at a 14 per cent reduced risk, compared to men, of developing physical illness; meaning that men are disadvantaged from a health perspective.

"The role of gender as a risk factor for illness is not always considered, but is an important element in medical research," said Dr. Matheson.

Dr. Matheson's findings appear online in the Journal of Epidemiology & Community Health. The study used data from the Institute for Clinical Evaluative Sciences where Dr. Matheson is an adjunct scientist.

About 25-30 per cent of the population lives with a mental health disorder in a given year. There is growing interest in studying the link between physical and mental illness as new studies indicate people with serious mental illness have higher rates of physical ailments such as metabolic syndrome, hypertension and cardiovascular, viral and respiratory diseases. Dr. Matheson was particularly interested in seeing whether gender also had an impact on the relationship between mental illness and onset of physical illnesses.

Her study used information from the 2000-2001 Canadian Community Health Survey and subsequent medical records to track the onset of four physical illnesses from 2001-01 to 2010-11 -- chronic obstructive pulmonary disorder, asthma, hypertension and diabetes.

"This study suggests the need for more research on the subject to fully understand connections between gender and complex health issues," said Dr. Matheson, a medical sociologist.

"The research also indicates a need for policy change to be more sensitive to these complex-needs patients," she said. "Short assessments often restrict physicians from addressing all potential health problems, limiting preventative care. There's potential for reduced health system costs if we can better meet the needs of patients with complex health issues."