In a new study of >600 000 Israeli adolescents, researchers found an inverse relationship between body mass index and acne.
Severely obese adolescents have 50% decreased odds of acne vs adolescents who are normal weight, according to a recent study published in the September issue of the Journal of the American Academy of Dermatology.
Acne vulgaris affects >85% of adolescents and young adults in the Western world, but the association between body mass index (BMI) and acne is unclear.
“Studies evaluating the risk of acne in overweight and obese adolescents have yielded conflicting results,” wrote Igor Snast, MD, Department of Dermatology, Rabin Medical Center-Beilinson Hospital, Petach Tikva, Israel, and colleagues. “In some studies, overweight and obesity conferred an increased risk of childhood and adult acne, and in others, it had a protective effect.”
Developing countries have also seen a rising interest in the BMI-acne association due to dramatic increases in adolescent obesity rates.
To determine the nature of this association, researchers in Israel conducted a nationwide, population-based, cross-sectional study based on medical data for >600 000 Israeli youths on compulsory army service between 2002 and 2015.
A total of 299 163 men and 301 241 women were enrolled in the study with a mean age of 18.9 years and 18.7 years, respectively at recruitment. Acne was diagnosed by a dermatologist in approximately 18% of men and 16% of women.
The majority of participants completed full military service (>88%), were born in Israel (>82%), and completed high school (>95%).
In the male cohort, 13.9% were overweight (BMI, 22-27.49 kg/m2) and 5.1% were obese (BMI, 27.5-32.49 kg/m2) or severely obese (BMI ≥35 kg/m2). In the female cohort, 12.6% were overweight and 4.3% were obese or severely obese.
Inverse relationship between acne and BMI
The results showed, “in youths, overweight and obesity are inversely associated with acne in a dose-dependent manner,” authors wrote.
Adolescents of both sexes who were overweight, obese, and severely obese had 20%, 35%, and 50% decreased odds, respectively, of having acne vs those with a normal BMI.
The proportion of adolescents with acne decreased as BMI increased, starting with approximately 20% of men in the underweight group having acne vs ~14% of men who were severely obese and ~17% of women in the low-normal group having acne vs ~11% of severely obese women.
For each 1-unit increase in BMI, the adjusted odds ratio (aOR) of acne decreased by 3.2% (95% CI, 2.9%-3.5%) in men and 2.6% (95% CI, 2.3%-3%) in women.
The results were similar to the unadjusted analysis findings, which showed the lowest odds of acne in severely obese adolescents (aOR for men, 0.53; 95% CI, 0.42-0.64; aOR for women, 0.5; 95% CI, 0.37-0.62).
Authors noted that the study lacked information on acne severity and on factors potentially confounding the BMI-acne relationship.
The inverse relationship between BMI and acne implies, “that metabolically active adipose tissue plays a protective role in acne,” researchers concluded.
To validate these results, further studies are needed that examine key variables in the BMI-acne association.