Eczema Exhibits Potential Protection Against Brain Cancer Development

For 2 important reasons—that brain cancer is so aggressive and its risk may be elevated in the presence of certain allergies—investigators of a meta-analysis set out to investigate potential connections between eczema and various brain cancers.

The risks of developing 3 types of brain cancer—glioma, meningioma, and acoustic neuroma—were reduced in the presence of patients 16 years and older having eczema, according to a meta-analysis published in BMC Cancer. This led the investigators determine that the inflammatory skin condition may confer some sort of protection against the aggressive cancer.

“The need to identify new reliable risk factors for early brain tumor interventions is urgent. Some reports indicate that eczema affects the cancer risk, but the results are controversial,” the study authors wrote. “Therefore, this study performed a meta-analysis to assess the relationship between eczema and brain cancer to clarify the risk factors.”

Their meta-analysis first involved a search of PubMed and Embase from inception through June 23, 2022. From this, they gathered 20 studies covering over 5 million patients that primarily took place in Europe; these data were independently reviewed, assessed, and pooled. All of the studies had to be in-human, observational studies that were published in English and considered how eczema and brain cancer development might be connected.

Overall, a reduced risk of brain cancer and of 3 particular types of it were seen if a patient had eczema.

The risk of brain cancer dropped by 18% (odds ratio [OR], 0.82; 95% CI, 0.77-0.87). However, the drop in risk was even steeper for glioma, acoustic neuroma, and meningioma.

For glioma, the risk dropped by 23% overall (OR, 0.77; 95% CI, 0.66-0.89). And although significant heterogeneity was seen for the 16 studies included in this analysis (P = .001; I2 = 59.6%), this disappeared (P = .515; I2 = 0.0%) when considering the risk among European patients, who saw their risk fall by 27% (OR, 0.73; 95% CI, 0.65-0.82).

The risk of meningioma fell by 26% (OR, 0.74; 95% CI, 0.66-0.84) in connection with eczema, and heterogeneity was not seen in the 9 studies used for this analysis (P = .996; I2 = 0.0%). Further, there was a significant drop in acoustic neuroma risk, 40% (95% CI, 0.41-0.88), and no heterogeneity in the 2 studies used for this analysis (P = .366; I2 = 0.0%)

In addition, age may be an influential factor for the relationship between eczema and brain cancer. A subgroup analysis showed that patients older than 16 years had a 21% reduced risk (OR, 0.79; 95% CI, 0.71-0.88), which the study authors said was a strong correlation. Further, a reduced risk of brain cancer was also seen among patients younger than 16 years, but it was smaller and deemed to not indicate as strong a correlation (OR, 0.94; 95% CI, 0.79-1.11).

Publication bias was not identified via Begg’s rank correlation (P > |z| = .362) or Egger’s linear regression (P = .183; 95% CI, −1.900 to 0.384) for any of the 20 studies included in the authors’ meta-analysis.

The authors put forth several theories for why eczema had convey a protective effect against brain cancer while also stressing that additional study remains a high priority. These included that abnormal cell growth is suppressed by an overactive immune system and that stronger allergic reactions are a more efficient defense mechanism against invasive toxins.

Because the study location was deemed a potential influential factor on outcomes, the authors conclude that their results “require validation in large randomized controlled trials.”

Reference

Zhu Y, Teng Y, Xu S, et al. Eczema as a protective factor for brain cancer: a meta-analysis. BMC Cancer. 2022;22(1):1360. doi:10.1186/s12885-022-10471-0

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