Obesity was associated with a significantly higher risk of rosacea, compared with a healthy weight, particularly when the weight was gained after age 18 years, according to an analysis of data from the Nurses Health Study II.
Investigators evaluated data on 89,886 women in the U.S. study from 1991 through 2005 – 5,249 diagnosed with rosacea – over 14 years to determine what, if any, relationship existed between body mass index (BMI) and rosacea risk.
As BMI increased, the risk of rosacea increased: Compared with participants with a BMI of 21.0 to 22.9 kg/m2 (considered a healthy weight), the risk of rosacea for those with a BMI of 25.0-29.9 (overweight) was 11% greater (95% confidence interval, 1.02-1.21), and among those with a BMI of 30.0-34.9, was 21% greater (95% CI, 1.09-1.34). The risk was 48% greater among those with a BMI of 35 or above (95% CI, 1.33-1.64). (A BMI over 30 is considered obese). The results were published in the December issue of the Journal of the American Academy of Dermatology .
The association between weight and rosacea risk was only significant after age 18 years, when the risk of rosacea increased 4% for every 10 pounds of weight gain, even after adjusting for BMI.
The investigators also found a significant relationship between waist circumference and rosacea risk that was independent of BMI, with the highest quintile of waist circumference associated with a 32% greater risk of rosacea, compared with the lowest quintile. Similarly, the highest quintile of hip circumference was associated with a 38% higher risk of rosacea, also independent of BMI. However there was no association between waist-to-hip ratio and rosacea risk.
While there were associations between the risk of rosacea and smoking, alcohol intake, and physical activity, the relationship between BMI and rosacea risk was not modified by these other risk factors.
Suyun Li, PhD, of the Guangzhou (China) Medical University School of Public Health and coauthors from the department of dermatology, Brown University, Providence, R.I.; and Brigham and Women’s Hospital, Boston, wrote that previous epidemiologic studies examining the interaction between obesity and rosacea have shown inconsistent results. Longitudinal studies on the issue had focused only on BMI and ignored other measures of central obesity.
“To our knowledge, this is the first cohort study on the association between obesity and risk for incident rosacea,” they wrote. “The study contributes to the understanding of rosacea etiology and informs clinical practice related to rosacea prevention and patient care.”
They suggested a number of different mechanisms that might explain how obesity increases the risk of rosacea, including the chronic, low-grade inflammatory state associated with obesity. “Adiposity can augment proinflammatory cytokine expression, such as interleukin 6 and tumor necrosis factor–alpha, both relevant to rosacea pathophysiology,” they noted. “Vascular changes associated with obesity might be another mechanism, considering obesity can lead to abnormalities of vascular function and structure, which might lead to the vasodilatation in rosacea.”
In the NHS II study, data are collected every 2 years, which the authors said ensured they had the most up-to-date information. While rosacea diagnoses relied on self-report, the authors said the study participants – nurses – were likely to have a high validity of self-reporting of rosacea. They acknowledged, however, that the lack of information on rosacea subtypes was a limitation of the study.
The study was supported by the department of dermatology, Brown University and a Nurses’ Health Study II grant. Dr. Li was supported by a research grant from the National Rosacea Society and the Dermatology Foundation. Another author declared having served as an investigator and receiving research funds from Sanofi and Regeneron; serving as a consultant for Sanofi and RTI Health Solutions, and having received honoraria from Astellas Canada, Prime, and Spire Learning. The remaining three authors had no disclosures.
SOURCE: Li S et al. J Am Acad Dermatol. 2017 Dec;77(6):1083-7.E5.