The association of Fe metabolism with obesity in children remains unclear. The present study aimed to assess the status of Fe metabolism parameters, the prevalence of anaemia, Fe deficiency (ID) and Fe-deficiency anaemia (IDA), and the associations of these variables with obesity in Chinese schoolchildren.

A cross-sectional study conducted in 5295 schoolchildren aged 7–11 years in Guangzhou, China, 2014–2015. Full data of anthropometric and Fe metabolic parameters were collected to assess obesity, anaemia, ID and IDA. Logistic regression models were established to determine the possible associations of anaemia, ID and IDA with obesity. Two-tailed P values of <0·05 was considered statistically significant.

Guangzhou City, China.

Schoolchildren aged 7–11 years (n 5295).

In this sample, mean Hb concentration was 128·1 g/l and the prevalence of anaemia, ID and IDA was 6·6, 6·2 and 0·6 %, respectively. Of the participants, 14·0 % were overweight and 8·8 % were obese. Importantly, obesity was associated with lower anaemia risk (adjusted OR = 0·553; 95 % CI 0·316, 0·968) but higher ID risk (adjusted OR = 1·808; 95 % CI 1·146, 2·853) after adjustment for confounders. No significant relationship was found between obesity and IDA.

Our results confirmed that anaemia and ID remain public health concerns among schoolchildren in Guangzhou, while IDA is remarkably less prevalent. Furthermore, obesity was associated with lower anaemia risk, but higher ID risk. More efforts should be made to prevent the onset of ID and obesity in the same individual, thus improving the health and fitness of children.