The prevalence of idiopathic intracranial hypertension (IIH) is dramatically higher in Black and Hispanic women vs people of other races and ethnicities, new research shows.
Investigators found IIH was nearly 3.5 times more prevalent in Black women and 2 times more prevalent in Hispanic women, a phenomenon that is likely explained by a combination of socioeconomic factors rather than race or ethnicity alone.
“While prior studies have demonstrated the differences in IIH between different races, ours is the first one to identify the association between socioeconomic determinants of health and the prevalence of IIH,” study investigator Venkatesh L. Brahma, MD, a neuro-ophthalmologist in Jersey City, New Jersey, told Medscape Medical News.
The findings were published online May 12 in Neurology.
Lack of Access to Healthy Food
Obesity is the main risk factor for IIH, which occurs most often in women of childbearing age. Socioeconomic and environmental factors, affect obesity risk and minority communities are more likely to have lower incomes and/or restricted access to healthy food, the investigators note.
To clarify the relationship between geographic and socioeconomic variables and IIH prevalence, the investigators conducted a retrospective cohort study at a single center in Philadelphia.
They examined electronic health records for women who visited a neuro-ophthalmologist on an outpatient basis between January 1, 2010, and July 1, 2018.
Among this group, the researchers identified women with IIH or papilledema. Women without IIH who were age 50 years or less served as the control group. Information on demographics including age, race, ethnicity, insurance status, weight, and body mass index (BMI) were also collected.
In addition, the investigators used the US Census Bureau’s geocoding program to convert patient addresses to US census tracts.
On the basis of public data available from agencies such as the US Department of Agriculture and the Centers for Disease Control and Prevention, the researchers identified census tracts with low access to healthy food (defined as food desserts) and those with a high proportion of unhealthy food (defined as food swamps).
A total of 223 women with IIH (mean age, 29 years; mean BMI, 37.4) and 4783 women without IIH (mean age, 40 years; mean BMI, 26.1) were included in the analysis.
Obesity, IIH Clearly Linked
Results showed a greater proportion of the women with IIH (52.9%) was Black or Hispanic compared with the control group (22.9%). Most patients with IIH lived in low-income census tracts (51.1%), and 20.6% had Medicaid insurance.
After adjusting for age, women with IIH were approximately four times more likely to be Black (odds ratio [OR], 3.96) and about twice as likely to be Hispanic (OR, 2.23) and live in low-income (OR, 2.24) or food swamp census tracts (OR, 1.54). However, they were less likely than women without IIH to live in a food desert (OR, 0.61).
After adjusting for race, ethnicity, and Medicaid status, patients with IIH were still more likely to be Black (OR, 3.45) or Hispanic (OR, 2.01).
However, the association between census tract characteristics and IIH was no longer statistically significant. When the researchers adjusted for BMI, the association between Black race and IIH remained significant (OR, 2.26).
“While our study does show that the women with IIH at our institution were more likely to be either Black or Hispanic, there are likely multiple factors for this association,” said Brahma. Clarifying the relationships between race, ethnicity, and IIH will require further research, he added.
Still, the association between obesity and the prevalence of IIH is already clear.
“More recently, studies have also identified relationships between obesity and socioeconomic factors,” such as income level and access to healthy food, Brahma said.
“Our study seems to identify similar relationships between socioeconomic factors and the prevalence of IIH,” he noted.
Need for Strategies to Mitigate Risk
Commenting on the findings for Medscape Medical News, Kathleen B. Digre, MD, chief of the Division of Headache and Neuro-ophthalmology, University of Utah, Salt Lake City, said the large, well-controlled study asked key questions about the social determinants of health.
“These kinds of studies that examine the social determinants are really important, since we know they have a direct effect on our health, but they are infrequently reported,” said Digre, who was not involved with the research.
However, the study’s retrospective design is a weakness, and because the population was limited to the Philadelphia area, the findings may not be generalizable to other locales, she noted.
“We have always known that there can be a racial and ethnic difference in IIH, so this is not surprising to me,” said Digre. “Obesity levels tend to run higher in these groups, and the fact that it is harder to get fresh fruits and vegetables also makes it challenging.”
The population’s economic level also plays a role, which indicates that the burden of IIH is partially related to disparities and access to better nutrition, she added.
“Neurologists should be aware of food swamps and bring this up to patients about diet in IIH,” Digre said. The findings also show that environmental social factors may contribute to obesity, she noted.
A question for future research is whether other social determinants of health can be addressed to reduce the effect of IIH on quality of life and to mitigate disparities.
“If access to fresh fruits and vegetables were to be brought into food swamps, could this change diet and weight for the community?” Digre asked.
The study was funded by the National Institutes of Health. Brahma and Digre have reported no relevant financial relationships.
Neurology. Published online May 12, 2021. Abstract