THE FACTS

Teenagers and young adults may be able to prevent acne by stepping on the bathroom scale.

Over the years, researchers have found that weight gain and moderate to severe acne — a problem that affects about one in five teenagers — go hand in hand, particularly among young women. While it is not entirely clear why, excess hormones most likely play a role.

The most recent study highlighting a link was published this month in The Archives of Dermatology and included roughly 3,600 teenagers. The researchers looked closely at their weight and its relation to their skin, factoring in several variables that could also play a role, including age, puberty and diet. High-sugar junk foods like candy and soda are not only linked to weight gain, for example, but are also known to worsen acne.

After adjusting for these and other factors that could affect acne risk, the researchers found that overweight or obese teenagers — particularly young women — were significantly more likely to develop acne than normal-weight adolescents. Another study of roughly 3,300 schoolchildren, published in 2006 in The European Journal of Dermatology, reached similar results, finding that a higher body mass index was a major risk factor for acne, “especially inflammatory lesions.”

Researchers have proposed several explanations for the link. One is that an excess of androgens caused by obesity provokes acne. As for why girls would be more greatly affected than boys, it is possible that having bad skin and being overweight cause them greater psychological strain, which in turn prompts the release of stress hormones that only worsen the problem, some researchers say.

THE BOTTOM LINE

In teenagers and young adults, a higher body mass index raises the likelihood of acne.