Complex lifestyle differences make study on potato consumption and risk of gestational diabetes difficult to interpret

Bao and colleagues’ interesting study uses data from a questionnaire that was sent every two years to nurses in the US and had a completion rate of over 90%.1 Because the 1991 questionnaire was the first to have dietary questions, effectively the minimum age for inclusion was 26 years or more, which reduces its generalisability to all women of child bearing age. The article details a policy for handling incomplete questionnaires and unrealistic responses, although it did not quantify how many women were excluded for these reasons. It also seems sensible to exclude women who have had previous gestational diabetes mellitus (GDM), not only because they may have changed their lifestyle but because they are more susceptible than the general population to developing GDM in future pregnancies.

Previous …