New York, Oct 22 (IANS): Children who receive antibiotics throughout the course of their childhood gain weight significantly faster than those who do not, says a new study.

The findings suggest that early antibiotics use may have a compounding effect on body mass index (BMI), a measure often used to determine whether someone is at a healthy weight.

"Your BMI may be forever altered by the antibiotics you take as a child," said study leader Brian Schwartz, professor at Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, US.

"Our data suggest that every time we give an antibiotic to kids they gain weight faster over time," Schwartz noted.

For the study, the researchers analysed health records of 163,820 children between three and 18 years old from January 2001 to February 2012.

They examined body weight and height (which are used to determine BMI) and antibiotic use in the previous year as well as any earlier years for which records were available.

At age 15, children who had taken antibiotics seven or more times during childhood weighed about three pounds (1.3 kg) more than those who received no antibiotics, the findings showed.

"While the magnitude of the weight increase attributable to antibiotics may be modest by the end of childhood, our finding that the effects are cumulative raises the possibility that these effects continue and are compounded into adulthood," Schwartz said.

Antibiotics kill off harmful bacteria but also those vital to gastrointestinal health. Repeated antibiotics use can forever change the microbiota, or the microorganisms that inhabit the body, thereby altering the way it breaks down food and increasing the calories of nutrients absorbed. This, in turn, can increase weight gain, the study explained.

The findings were detailed online in the International Journal of Obesity.