Consumption of sugar-sweetened beverages has been associated with increased risk of obesity and type 2 diabetes. Now, a new study finds girls who frequently drink such beverages are likely to start menstruation earlier than those who do not consume sugary drinks, potentially putting them at higher risk of breast cancer.
The research team, led by Karin Michels, associate professor at Harvard Medical School in Boston, MA, publishes their findings in the journal Human Reproduction.
According to the Centers for Disease Control and Prevention (CDC), approximately half of the US population consumes sugary drinks on any given day, including around 60% of females aged 2-19 years.
Sugar-sweetened drinks have grown to be a major public health concern, with numerous studies associating the beverages with increased weight gain in children and adolescents. In October 2014, Medical News Today reported on a study that also linked sugary drink consumption to premature aging of immune cells.
This latest study, however, is the first to associate sugary drink consumption in girls with the age of first menstruation, or menarche.
To reach their findings, Prof. Michels and her team analyzed 5,583 girls aged 9-14 years who were a part of the Growing Up Today Study, which involves 16,875 children of participants from the Nurses Health Study II.
At study baseline in 1996, none of the girls had started menstruation. They were followed-up until 2001, by which point 159 girls (3% of the participants) had started menstruation.
At several points during the 5-year study period, the girls were required to complete a dietary questionnaire that disclosed their consumption of sugary drinks - drinks that contain added sugars like sucrose, glucose and corn syrup.
They were asked how often they consumed a serving of these drinks, such as one glass or can of soda or one glass, can or bottle of sweetened ice tea. To assess the effects of artificially and naturally sweetened drinks, the girls were also asked how often they consumed a serving of diet soda or fruit juice.
1.5 servings of sugary drinks a day linked to starting menstruation 2.7 months earlier
The researchers found that, on average, girls who consumed more than 1.5 servings of sugar-sweetened beverages started menstruation 2.7 months earlier than girls who consumed two or fewer servings of these drinks each week.
What is more, the team found that at any age between 9 and 18.5 years, girls who consumed more than 1.5 servings of sugary drinks each day were approximately 24% more likely to begin menstruation in the next month than girls who drank two or fewer servings each week.
Overall, girls who drank the most sugary drinks started menstruation aged 12.8 years, while those who drank the least began menstruation aged 13 years.
The team found no association between consumption of artificially and naturally sweetened drinks and age of first menstruation.
These results remained significant even after the researchers accounted for other factors that could influence the age of first menstruation, such as body mass index (BMI), birth weight, height physical activity, ethnicity/race, family composition and how often the girls ate dinner with their family.
Commenting on the findings, Prof. Michels says:
"Our study adds to increasing concern about the widespread consumption of sugar-sweetened drinks among children and adolescents in the US and elsewhere.
The main concern is about childhood obesity, but our study suggests that age of first menstruation 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."
The team notes sugary drinks have a higher glycemic index than naturally sweetened drinks, which can trigger a rise in insulin concentrations. An increase in insulin concentrations can lead to a rise in concentrations of sex hormones, which can cause earlier menstruation - a potential explanation for the team's findings.
Findings may indicate an increased risk of breast cancer
The researchers say their findings raise concern as earlier menstruation has been associated with increased risk of breast cancer.
They say a 1-year decrease in age at first menstruation is estimated to raise the risk of breast cancer by 5%. "Thus, a 2.7-month decrease in age at menarche likely has a modest impact on breast cancer risk."
"The amount of sugar-sweetened beverages consumed by girls in our highest category of consumption, more than 1.5 servings per day, however, is likely low compared with consumption in certain other populations, in which we would expect an even more dramatic decrease in age at menarche," they add.
"Most importantly, the public health significance of sugar-sweetened beverage consumption at age at menarche, and possibly breast cancer, should not be overlooked, since, unlike most other predictors of menarche, sugar-sweetened beverage consumption can be modified."
In December last year, MNT reported on a study claiming the age at which women start menstruation may affect their risk of hypertension, heart attack and stroke.