People over the age of 50 with low vitamin D levels are no more likely to have a specific type of low blood pressure that affects almost one-third of older adults, a new Irish study has found.

In the largest study of its kind to date, researchers from The Irish Longitudinal Study on Ageing (TILDA) at Trinity College Dublin looked at the impact of vitamin D on orthostatic hypotension (OH).

TILDA is an ongoing study of adults over the age of 50 in Ireland.

OH is a chronic condition estimated to affect 30% of older adults. It refers to a significant drop in blood pressure upon standing and it has been linked with falls, fractures and mortality.

Recent research has suggested that vitamin D may help with the condition. This vitamin is essential for good bone health and is thought to have other beneficial health effects also.

The main source of vitamin D is ultraviolet B (UVB) radiation from the sun, however this can be affected by factors such as sunscreen use, cloud cover and seasons.

Meanwhile, foods that provide the vitamin include fatty fish such as salmon and mackerel and fortified foods, such as breakfast cereals and some dairy products.

Many older Irish people are deficient in vitamin D, with one in eight deficient at any given time, and one in four deficient during the winter period.

The researchers found that older adults who were deficient in vitamin D were more likely to be smokers, take medication for high blood pressure and have more cardiovascular problems than those with sufficient levels.

However, they also found that those with low vitamin D levels were no more likely to have OH than those with normal levels. It also found that vitamin D supplement use was not linked with OH.

"This is the largest ever study exploring vitamin D and OH. In the older Irish population we see no association. This is important as it is essential to know what is and is not associated with vitamin D when trying to devise and recommend intakes for the population based on health outcomes.

"Recently, vitamin D has been seen as the cure-all health panacea, however it makes perfect biological sense that it cannot be associated with everything," explained the study's lead author, Dr Eamon Laird.

While no link was found between vitamin D levels and OH, the researchers pointed out that the vitamin may still have a role to play in the management and possible prevention of the condition.

"For example, those with OH are more likely to fall and also sustain fractures and the strongest evidence for the health benefits for vitamin D exists for bone health and muscle function. Thus, checking vitamin D levels and optimising vitamin D status for bone health and muscle function is important in this high-risk group," commented Principal TILDA investigator, Prof Rose-Anne Kenny.

Details of these findings are published in the journal, Hypertension.