Certain eating habits, high levels of stress and exposure to pollution are among the greatest factors associated with acne, researchers say.
They studied links to acne in more than 6,700 people from six countries in Europe and the Americas. The analysis showed that many more people with acne consume dairy products each day than those without acne -- 48.2% versus 38.8%.
The same was true for soda, juices or syrups (35.6% versus 31%); pastries and chocolate (37% versus 27.8%); as well as other sweets (29.7% versus 19.1%).
The study also found that 11% of acne sufferers consume whey proteins compared to 7% of those without acne. And 11.9% of acne sufferers use anabolic steroids versus 3.2% of others.
Exposure to pollution and stress was also more common among people with acne, and they were also more likely to use harsh skin care practices.
The findings reflected an association with acne, but not a cause-and-effect link. The study was scheduled to be presented Saturday at a meeting of the European Academy of Dermatology and Venereology (EADV), in Madrid.
Lead author Dr. Brigitte Dreno, head of dermatology at University Hospital of Nantes in France, noted that acne is one of the most common reasons people see a dermatologist.
"Its severity and response to treatment may be influenced by internal and external factors, which we call the exposome," Dreno said in a meeting news release. "For the first time, this study allows us to identify the most important exposome factors relating to acne from patient questioning prior to any treatment prescription."
Previous research has suggested that tobacco use is an acne trigger, but this study did not link tobacco with acne.
Acne affects about 1 in 10 people worldwide, and as many as 40% of adult women.
"Understanding, identifying and reducing the impact of exposome is important for an adequate acne disease management as it may impact on the course and severity of acne as well as on treatment efficacy," said Dreno, who is also chair of the meeting's Scientific Programming Committee.
Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.
The American Academy of Family Physicians has more on acne.