People living Dublin 8 and Lucan are up to four times more deficient in vitamin D than other parts of the greater Dublin area, new figures show.
The research published on Wednesday also shows younger people have “considerably” lower levels of the vitamin than those aged over 50 and women had “significantly” higher levels than men.
It is the first time in Ireland a visual map of the Vitamin D status for people living in the greater Dublin area has been developed.
The research was carried out by Trinity College Dublin and St James's Hospital using a combination of geo-mapping and data from more than 5,200 people in 2015.
It showed one in eight of the population of greater Dublin and Co Kildare were found to be vitamin D deficient with an overall vitamin D deficiency of 15.2 per cent during winter and 10.8 per cent in the summer.
The months of October to February are defined as winter and March to September as summer in the study.
The report said the rates of inadequate vitamin D were “alarming” due to the growing number of chronic health conditions associated with deficiency of the vitamin such as heart disease, diabetes and cancer. Severe vitamin D deficiency can cause rickets in children and osteomalacia, or softening of the bones, in adults.
Vitamin D is essential for healthy bones, teeth and muscle.
The figures revealed in Dublin 8, which include areas such as Inchicore, Kilmainham, Portobello, Rialto, Islandbridge and South Circular Road, the number of people deficient in vitamin D were significantly higher at 26.8 per cent than the average (of 15.2 per cent).
Lucan in west Dublin followed in second place with 21.7 per cent of residents deficient in the vitamin.
Winter months
Dublin 20, which includes areas such as Palmerstown and Chapelizod, was third highest with 20.7 per cent of the population deficient in the vitamin during winter.
However in Dublin 16, which includes areas such as Ballinteer, Ballyboden, Dundrum, Rathfarnham and Churchtown, the deficiency rate was 7.8 per cent in the winter.
The lowest rate in the study was 7.6 per cent of the residents in Leixlip in Co Kildare were found the have the vitamin deficiency.
Dr Eamon Laird from Trinity College Dublin, who is one of the authors of the study, said there were a number of possible reasons for the differences between areas in Dublin.
“Other studies have shown an association between social deprivation and lower vitamin D, possibly due to diet as vitamin D-rich foods such as oily fish or fortified foods tend to be more expensive,” he said.
“Also, these locations in Dublin are more ethnically diverse compared to other areas, with higher numbers of non-Caucasians. Increased skin pigmentation plus ethnic lifestyle choices such as traditional clothing and/or dietary habits can also increase the risk of deficiency.”
The report highlighted men had an average of 23-27 per cent lower levels of vitamin D than women at some city locations.
Dr Martin Healy, the principal investigator of the study and principal biochemist at St James's Hospital, said one of the reasons for the figure is that women were much more likely to visit their GP than men.
“So women can be more aware of health issues,” he said.
The study also revealed participants aged over 50 years old had better vitamin D levels than younger people, aged between 18 to 50-years-old, regardless of their city location.
Dr Healy said this may be due to younger people working indoors with less exposure to sunlight or a poor diet.
“Also there’s more of awareness from the older age group about the health benefits (of vitamin D),” he said.
The Health Service Executive (HSE) advises the best source of vitamin D is summer sunlight but for people to take care and not let their skin turn red or get burnt.
It said foods such as oily fish, eggs and fortified breakfast cereals are a good source of the vitamin.
The HSE advises taking high doses of vitamin D for long periods of time could weaken your bones.
The organisation said taking 25 micrograms (0.025mg) or less a day of vitamin D supplements was unlikely to cause any harm.
Other areas included in the study were Dublin 6/6w, Dublin 12, Dublin 14, Maynooth and the rest of Co Kildare.
