People diagnosed with Lyme disease in England and Wales tend to be older, white women living in rural, relatively affluent areas.
An analysis of hospital records found that the disease is most commonly diagnosed in women aged between 61 and 65, with a second peak in incidence in girls aged between 6 and 10.
Researchers at the University of Liverpool and Public Health England looked at the records of 2259 people diagnosed with Lyme disease at National Health Service hospitals in England, and 102 people in Wales, between 1998 and 2015.
They found that 96 per cent of patients self-identified as white. Significantly more cases were recorded in hospitals in rural locations than in urban areas, and there were more cases in richer areas than in areas of higher deprivation.
The highest incidence of Lyme disease was in south-west England, where there were 3.13 cases a year for every 100,000 people.
Overall, the team found there was a significant increase in the disease’s incidence in England and Wales during the course of the study, from 0.08 cases per 100,000 people in 1998 to 0.53 cases per 100,000 in 2015.
John Tulloch at the University of Liverpool says he is confident the results reflect the groups that are most likely to be at risk of infection, but there needs to be more research to understand why more girls and women in certain age groups are diagnosed.
“It may be due to a result of sex differences in health-seeking behaviour and this result needs to be further explored,” he says. Girls and women of these age groups and geographical areas may spend more time outside for leisure activities.
The picture in relation to ethnicity is still unclear as this is the first time this has been studied in the UK, says Tulloch. “We do not know whether this is broadly representative of the whole Lyme disease-affected population or just of those who have contact with NHS hospitals.”
In July, an analysis of Lyme disease cases recorded in primary care in the UK concluded that the infection may be three times more common than previously thought. Sally Cutler at the University of East London says this kind of analysis is likely to be a less robust way to investigate disease incidence than hospital records, which were used in the new study. “The true incidence probably lies somewhere between the two [studies]”, she says.
It can be difficult to accurately diagnose the disease, says Cutler. “A lot of the clinical manifestations of Lyme disease can overlap with other diseases – especially in older women – and there’s no agreement on what criteria to include when confirming a positive case.” This could mean some women are being diagnosed as having the disease when they actually have a different condition.
Although the study points to who is most at risk of Lyme disease, says Tulloch, “tick awareness is important for everyone, regardless of age, ethnicity and gender, when spending time outdoors in areas where ticks might be found”.
Lyme disease is caused by bites from ticks infected with Borrelia burgdorferi bacteria. The symptoms can include a flu-like illness and a circular red rash resembling the bullseye of a dartboard.
Journal reference: BMC Public Health
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