Some GPs may have been putting their patients at increased risk of skin cancer by giving non-standard advice on summer sun protection, research indicates.
It is thought this arose through confusion over the emerging evidence of the potentially wide benefits of having enough vitamin D, most of which is obtained by exposing our skin to the sun for short periods, at least during summer.
The Health Ministry issued an official consensus statement on vitamin D and sun exposure in March, partly because draft findings of the Otago University survey of more than 1000 general practitioners had caused serious concern.
The survey, published this month, found that for summer 2 per cent of GPs told their patients not to use sun protection at any time; 17 per cent advised using sun protection only "most of the time" during periods of peak ultra-violet (UV) radiation, and also to receive some direct sunlight at those times.
"Most New Zealand GPs (70 per cent) and more than in New South Wales (55 per cent) advised the currently recommended summer sun protection strategy ('to use sun protection at all times during peak UV')," said Dr Anthony Reeder and colleagues, reporting on their survey in the journal BioMed Central Family Practice.
Other findings were that 10 per cent of GPs were recommending less sun protection year-round because of recent information about vitamin D, while 43 per cent said they were "not at all confident" about their vitamin D knowledge.
Vitamin D is important for healthy bones, but a succession of studies have indicated associations between low levels of the vitamin and various conditions including bowel cancer, heart disease, multiple sclerosis, type 2 diabetes and mood and cognitive problems.
Nearly a third of New Zealand children and just over a quarter of adults have insufficient vitamin D, while a further 5 per cent of adults have a deficiency. New Zealand has one of the world's highest incidence and death rates for malignant melanoma - the deadliest form of skin cancer - for which sunburn is a risk factor.
Cancer Society national health promotion manager Jan Pearson said the findings on GPs' sun-protection advice were a big concern and could have increased people's skin cancer risk. They reflected confusion over sun protection because of new evidence on vitamin D.
Implementing the researchers' suggestions, the society and other health groups were working on "how we can get the messaging across to GPs more clearly".
Asked if an individualised online calculator was needed so people could check their sun protection and vitamin D needs depending on their skin type and other factors, she said this would be useful, but the society had no money for such a scheme.
The Cancer Council of Queensland has a free smartphone application which allows people to check the UV level and weather forecast in their locality.