Recent work suggests that environmental circumstances can alter immune activity in ways that may or may not be important in various immune disorders such as asthma, allergy, Type 1 Diabetes, autoimmune demyelination and multiple sclerosis. It is well established that asthma and hayfever are more common in modern times. It also appears that other immune disorders, including Type 1 Diabetes, Crohn's colitis and multiple sclerosis are becoming increasingly common. The latter three disorders occur when the body's own immune system attacks body organs: the pancreas, bowel lining and central nervous system respectively.

The marked increase in immune disorders over the past fifty years is thought to reflect modern environmental and lifestyle factors, rather than changes in diagnosis.

Some immune disorders vary by region in Australia.

Population-level surveys indicate intriguing differences in the rates of various immune disorders by region in Australia. Regional differences have been detected for Type 1 Diabetes and asthma in the Australian Bureau of Statistics 1995 National Health Survey. A marked regional variation (up to eight-fold) in multiple sclerosis rates has previously been documented.

Australia is an excellent location for a study of environmental effects on health because our country has environmental diversity but a common health care system.