Sugary drinks may be causing girls to start menstruating earlier, new research suggests.
A study of girls aged nine to 14 found that those drinking more than 1.5 sugar-sweetened beverages a day had their first period 2.7 months earlier than those consuming two a week or fewer.
The discovery is important because earlier onset menstrual periods have been linked to an increased risk of breast cancer later in life. Sugary drinks are also said to be contributing to childhood obesity.
US lead researcher Dr Karin Michels, from Harvard Medical School, said: "Our study adds to increasing concern about the widespread consumption of sugar-sweetened drinks among children and adolescents in the USA and elsewhere.
"The main concern is about childhood obesity, but our study suggests that age of first menstruation (menarche) occurred earlier, independently of body mass index, among girls with the highest consumption of drinks sweetened with added sugar.
"These findings are important in the context of earlier puberty onset among girls, which has been observed in developed countries and for which the reason is largely unknown."