The study led by Professor Tomoko Imai investigated the association between rice consumption and obesity prevalence across countries (Eating more rice may help fight obesity: Study, May 2).

The authors concluded that "the prevalence of obesity was significantly lower in the countries with higher rice supply even after controlling for lifestyle and socio-economic indicators".

The study did not conclude that rice consumption prevents obesity, as suggested by the Bloomberg article, nor did it conclude that eating rice can "fight" obesity, as suggested by The Straits Times headline.

Populations that tend to consume less rice are likely to have fundamentally different dietary cultures from those that consume more rice. The difference in fat, sugar and alcohol consumption may act as confounders that account for the perceived difference, if these were not adjusted for.

It is likely that it is the entire Eastern dietary culture, compared with the Western dietary culture, that accounts for the difference in obesity rather than the rice itself. We also need to consider the other genetic and environmental differences that could confound the results.

We must also consider how "rice consumption" was quantified. Was this a survey involving a handful of participants from each country, and if so, how were these participants chosen?

For these reasons, healthcare workers and policymakers are understandably cautious in interpreting many of these studies.

Also, reporters need to be more circumspect when reporting medical and healthcare studies.

Cho Jiacai (Dr)