All patients included in the study were questioned at baseline regarding their height and race/ethnicity. Weight, smoking status, and physical activity, and diagnoses of hypercholesterolemia, type 2 diabetes, cardiovascular disease, and asthma were monitored biennially.
Overall, patients with higher EDIP scores were found to have higher BMI, lower physical activity, and alcohol use, as well as increased rates of hypercholesterolemia and hypertension.
“Though we found no convincing evidence for an association with EDIP score for any of the investigated diseases, the results followed an internal pattern consistent with our hypotheses that higher EDIP scores would have more of an association with psoriatic disease than with atopic dermatitis,” the researchers wrote.
Citing recent evidence gathered in studies, such as the French NutriNet-Santé study, which demonstrated proinflammatory effects similar to those measured with the EDIP in cases where there was low adherence to the Mediterranean diet, the authors attributed their contradictory findings to “important methodological differences.” Unlike the NutriNet-Santé study, which classified psoriasis by severity, Ms. Bridgman and her colleagues examined the overall risk of incident psoriasis. “It is possible that a dietary index associated with more Th-2 inflammation would yield different results,” they noted.
The large sample size, prospectively collected dietary, and psoriatic disease data, as well as the ability to adjust for important confounding factors, were included among the strengths of the study.
That the participants were limited to U.S. women could be considered a limitation because the results may not be generalizable to other populations. The results also may not be relevant to child-onset disease because the patient population included only cases of adult-onset atopic dermatitis. Questionnaire-based diagnoses increase the likelihood of misclassification, so “dilution of the case pool with false-positive cases would bias our results towards the null,” they added.
Ultimately, the authors noted that proinflammatory diet may be associated with other health risks, but these do not warrant counseling patients concerning their possible impact in cases of psoriatic disease or atopic dermatitis.
The study was funded by Brown University department of dermatology and from Regeneron, Sanofi, the National Institutes of Health, and the National Cancer Institute. Two coauthors, one of whom has a patent pending for the nix-tix tick remover, disclosed ties with various companies.
SOURCE: Bridgman AC et al. J Am Acad Dermatol. 2019 Feb 21. pii: S0190-9622(19)30329-9.