New Zealand death rates soar in the winter months and researchers believe cold, damp and poorly maintained homes are at least partly to blame.
Otago University researchers analysed deaths over a 20-year period and found 1600 more people died during the four winter months.
The "excess winter mortality" death rate is among the highest in developed countries which measure it.
The study, published in the BMC Public Health journal, found that the bulk of the deaths were caused by circulatory, respiratory illnesses and infectious diseases.
Infants and elderly people accounted for many of those who died during winter, and almost 10 percent more women died in winter than men, the study found.
"Excess winter mortality is a huge problem," said Otago University researcher Michael Baker.
"It accounts for four times the number of people who die in the road toll. One of the problems, though, is that it's not immediately clear all the reasons for it."
Dr Baker said he was now doing research to understand what impact insulating a house had on death rates during winter.
A 2006 study by the Commissioner for the Environment Morgan Williams showed more than a million New Zealanders were living in homes which were damp and cold -- below the minimum temperature of 18degC recommended by the World Health Organisation.
At 16degC, the risk of respiratory illness increases. Below 12degC, there was a higher risk of strokes and heart attacks, the study said.
Christchurch Hospital social worker Anne Crawford told The Press that every winter she and her colleagues dealt with a deluge of respiratory patients struggling to keep their homes warm.
Otago University researcher and healthy-housing expert, Philippa Howden-Chapman, said there were many big, wooden houses in New Zealand which were hard to heat. New Zealanders also deferred maintenance more than in other developed nations.
Sharp increases in the cost of living would mean people were even less likely to pay to maintain or insulate their properties, she said.
"The indoor environment has a huge impact on people's health whether they get sick and whether they stay sick."
