January 28, 2015

expert reaction to study on sugary beverages and age at onset of menstruation

A paper published in the journal Human Reproduction has examined an association between intake of sugar-sweetened beverages and the age of onset of menstruation. The researchers report a younger age for those with a higher intake which they suggest is independent of BMI, but recognise that there may be confounding factors not accounted for.

Prof. Ieuan Hughes, Emeritus Professor of Paediatrics, University of Cambridge, said:

“The total group had a median age of menarche of 12.7, which is absolutely the population norm and has not changed for the past 40-50 years. But the unadjusted sample in the study actually had a higher value ( 13.1) which ‘disappeared’ when a whole raft of adjustments were made based on the SSB intake at the lowest and highest end of the range. How biologically relevant is a difference of 2.7 months?

“Many confounders are controlled for but no data on effect of migration (phenomenon reported in Europe on age of menarche) and locality and parents’ occupations. The authors admit that future studies should examine the impact of early childhood nutrition on menarche. It seems to me that the observation in this study suggests that it is weight related so that the message is clear about the dangers of such sugary drinks. I think the reference to breast cancer is overly alarmist though.”

Dr Ken Ong, Programme Leader & Paediatric Endocrinologist, MRC Epidemiology Unit, University of Cambridge, said:

“This is a very large study, which was representative across the USA, and the findings are strongly statistically significant. From previous research we know that sugar-sweetened beverages (SSB) intake promotes weight gain, and that weight gain promotes early puberty in girls – so a ‘SSB-to-puberty’ link is expected (although not previously shown).

“The surprise here is the claim that the association is independent of childhood size – i.e. that there is a more direct effect of SSB on puberty. This is unexpected.

“The main limitation is that the crucial factors, childhood height and weight, were not measured in their study, but were self-reported by the families. Errors in this reporting could explain the lack of the expected role of weight/BMI in explaining the SSB-puberty link.

“We do have causal evidence (from other studies) that SSB intake promotes weight gain in children – so clearly excessive SSB intakes should be avoided. We also know that rapid weight gain promotes early puberty, so reducing SSB might well help to avoid early puberty. But we don’t yet know if and how SSB might influence puberty directly, separate to body size.”

‘Sugar-sweetened beverage consumption and age at menarche in a prospective study of US girls’ by Carwile et al. published in Human Reproduction on Wednesday 28th January 2015. 

Declared interests

None declared