A major New Zealand study into multiple sclerosis (MS) may confirm suspicions that South Islanders are more likely to get the disease than those from the North.
The degenerative disease, which affects an estimated 3500 New Zealanders, appears to strike more often in populations further from the equator, with Scotland reporting one of the highest rates of MS in the world.
A New Zealand study has found people from Otago were 2 1/2 times as likely to get the disease as those from the Bay of Plenty.
For the first time, a major research team is attempting to survey every MS patient in New Zealand.
As well as questions about income and lifestyle, it will examine where each person has lived throughout their life. It will also study racial origins.
Internationally the disease is more prevalent amongst Caucasians. It is uncommon in Asians and believed to be rare in Maori and Pacific Islanders.
Christchurch neurologist Bruce Taylor said the study was the largest of its kind in the world.
"It is a very, very exciting study and a really important study for New Zealand."
Taylor said the cause of the regional variation was unclear. One theory was that a lack of sunshine during winter caused a critical shortage of vitamin D in developing immune cells affecting their regulation. It appeared most important in the first 15 years of life.
MS also had a genetic component and was typically triggered in those susceptible by an "insult to their immune system", such as an infectious illness.
Multiple sclerosis patients have scars in their brain and spinal cord, where bouts of inflammation have healed. The inflammation damages the nerve fibres leading to symptoms such as fatigue, poor balance or blurred vision. The inflammation heals spontaneously allowing symptoms to ease or disappear.
It can also leave permanent impairment, increasing with each episode. There is no cure, though MS is rarely fatal and most people with MS have a near-normal life expectancy.
The use of MRI had drastically reduced the time to diagnosis from as long as 10 years after the first symptoms appeared to about one year.
Taylor and his team want to contact all those with a confirmed diagnosis of MS by Census Day, March 7, 2006. This would allow the MS population to be directly compared with that of the general population.
Taylor hoped data collection in the $400,000 study would be complete by July next year.
Amongst those who have completed a questionnaire is former Press journalist John Brown, diagnosed with MS in 1966, aged 28.
The doctors told his wife he would be in a wheelchair within two years and dead by the age of 40 and advised her not to tell him.
He said it was "quite some time" before he finally learnt what was causing tingling in his arms and legs and split vision.
Despite increasing difficulty walking, he did not become totally dependent on a wheelchair for 30 years and was able to continue working as a journalist and travelled extensively.
Episodes of serious depression, sometimes leading to hospitalisation, were a symptom of his MS and were more incapacitating than paralysis, said Brown.
Now 68, and paralysed from the waist down, Brown remained articulate and active, travelling daily from his Sydenham home by powered wheelchair. Last month he had a feature published in The Press about the poor pay for personal caregivers.
Source: The Press, New Zealand