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Idiopathic intracranial hypertension on the rise, women especially vulnerable

Reuters Health - 21/01/2021 - Idiopathic intracranial hypertension is on the rise and tracks with increasing obesity rates, a new study finds.

An analysis of 35 million patient-years of data from more than 3 million Welsh patients revealed that the brain pressure disorder had increased more than six-fold during a 15-year period, according to the report published in Neurology.

"There has been a significant increase in idiopathic intracranial hypertension (IIH) in recent years with a six-fold increase in the prevalence of IIH in Wales between 2003 and 2017," said coauthor W. Owen Pickrell of Swansea University in Wales.

"This increase is multifactorial but likely predominately due to rising obesity rates," Pickrell said in an email.

"Some people who are overweight may be more likely to develop this because the elevated pressure in the abdomen translates to increase pressure in the brain, but this is not always the case for every patient," said Dr. Anna Pace, an assistant professor in the department of neurology at the Icahn School of Medicine at Mount Sinai who was not involved in the study.

IIH is also associated with increasing (socioeconomic) deprivation, Pickrell noted. "In women, IIH is associated with increasing deprivation even after adjusting for obesity, suggesting additional etiological factors associated with deprivation apart from BMI," he said.

It is currently not known why the condition is more common among those who are obese and among women, Pickrell said.

Symptoms of idiopathic intracranial hypertension can mimic those of a brain tumor, causing chronic disabling headaches, vision problems and, in rare cases, loss of vision. Overall, the condition is most often diagnosed in women of childbearing age and the treatment is often weight loss. Occasionally, surgery is required.

To take a closer look at IIH, Pickrell and his colleagues turned to a healthcare database that contains information for the entire Welsh population. Information on socioeconomic status came from the Welsh Index of Multiple Deprivation, 2011 version. BMI was obtained from primary care healthcare records.

The researchers identified 1,765 people diagnosed with the condition between 2003 and 2017, 85% of whom were women. For each person with the condition, the researchers identified three controls matched by age, gender and socioeconomic status.

Overall, the prevalence and incidence of IIH in 2017 were 76 per 100,000 and 7.8 per 100,000, respectively. That's a significant increase over 2003 prevalence and incidence, 12 per 100,000 and 2.3 per 100,000, respectively.

IIH prevalence was associated with increasing BMI and increasing socioeconomic deprivation. The odds ratio for developing IIH in the least deprived quintile compared to the most deprived quintile, adjusted for gender and BMI, was 0.65.

Among those diagnosed with IIH, 9% had cerebrospinal fluid shunts and less than 2% had bariatric surgery. The odds for unscheduled hospital admissions were more than five times higher in the IIH cohort compared to controls.

"The worldwide prevalence of obesity nearly tripled between 1975 and 2016 and therefore these results also have global relevance," the researchers point out. They add that along with rising obesity rates, the increase in IIH incidence "may also be attributable... to raised awareness of the condition and greater use of digital fundoscopy at routine optometry appointments."

SOURCE: https://bit.ly/3iAN81h Neurology, online January 20, 2021.

By Linda Carroll

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