A school nurse measures the weight of a kindergartner. (Steve Miller/Associated Press)

Schools should continue to send home "fat letters" indicating a child is overweight or obese despite legislative moves in an American state to ban the controversial screenings, a pediatrician says.

A bill currently before the Massachusetts legislature would bar the state's public health department from collecting data on height, weight or calculating BMI (body mass index) in public school children.

"The passage of legislation to prevent BMI screening and surveillance would further compromise efforts to track long-term BMI data, evaluate these programs, and empower parents with the knowledge and resources to promote healthy lifestyle early in the lives of their children," Michael Flaherty of Baystate Medical Center in Springfield, Mass., concludes in a commentary in today's issue of the journal Pediatrics.

"It is time to put aside this pride for the future of children's health."

The letters have been deemed "fat letters" in the state and featured on late night comedy shows and media reports at the same time the prevalence of obesity is increasing in American children, Flaherty wrote.

While acknowledging BMI-measurements are "fraught with social and political concerns," Flaherty said several studies have shown childhood BMI, particularly at the highest percentages, correlate with adult obesity and development of heart disease later in life.

Currently in the U.S., 21 states have policies or recommendations on collecting the data.

St. Stephen High School in St. Stephen, N.B., is evaluating teens for improvement using health indicators including BMI and resting heart rate. The project is capturing the attention of observers. 

Toronto Public Health's website says its student survey is meant to provide information about students as a whole, not individuals, adding city's public health nurses will not routinely disclose height and weight information.