SAN FRANCISCO (FRONTLINE MEDICAL NEWS) – Children were more likely to experience a fracture if they were prescribed antacids before age 1 year, according to a study of military families.

The large study revealed that use of proton pump inhibitors (PPIs) before age 1 year was linked to a 22% increased risk of fracture, compared with those not prescribed antacids. Similarly, children prescribed both PPIs and H2 blockers before age 1 year were 31% more likely to have a fracture compared to those not taking the drugs.

“A lot of data are coming out that proton pump inhibitors are not quite as benign as we used to think, and we are seeing that fracture risk is increased with use,” U.S. Air Force Capt. Laura Malchodi, MD, a pediatrics resident at Walter Reed National Military Medical Center in Bethesda, Md., told colleagues at the Pediatric Academic Societies meeting.

Antacid use has been increasing among both adults and children, but the biggest rise has been in children under age 1 year, she said. Previous research into adult use of antacids has revealed an increased incidence of fractures, so Dr. Malchodi investigated the incidence of fractures in children under age 1 year among those who had taken PPIs, H2 blockers, neither, or both.

“What this means for doctors is that when you do start to think of using proton pump inhibitors or any antacid therapy in children, we should really think of limiting it to one type if possible – H2 blockers are now preferable – and for the shortest amount of time as possible,” Dr. Malchodi said of her findings.

The retrospective study’s cohort comprised 874,447 children born between 2001 and 2013 who had been in the U.S. Military Health System for at least 2 years. Children who took antacids after age 1, spent more than a week in a neonatal intensive care unit, or had nonaccidental trauma (abuse) or osteogenesis imperfecta were excluded.

Ninety percent of the cohort had not received prescriptions for any antacids (789,631 children) in their first year of life, and 1.2% had received prescriptions for both PPIs and H2 blockers before age 1 year. Of the remaining children, 7.7% had received prescriptions for H2 blockers, and 0.8% for PPIs.

The children who had and had not been prescribed antacids were similar in median years enrolled in the system, but nearly twice as many who received antacid prescription had been preterm (6.4% vs. 3.5%, P less than .05). Similarly, 3.7% of those prescribed antacids had a low birth weight, compared with 2.2% of those not prescribed antacids (P less than .05). The median age of fracture also differed for the two groups: 3.9 years for those prescribed antacids and 4.5 years for those not (P less than .05).

In using medical records during their analysis, the researchers excluded follow-up visits for the same fracture within the previous 6 months. Before adjustment for covariates, boys had a slightly increased risk of fracture (hazard ratio [HR], 1.08), and those with a previous fracture had an 85% increased risk (HR, 1.85). Compared with children not prescribed antacids, those prescribed PPIs had a 23% increased risk of fracture (HR, 1.23), and those prescribed H2 blockers had a 13% increased risk (HR, 1.13). Those prescribed combination antacid therapy had a 32% increased risk of fractures (HR, 1.32).

Adjustment for preterm birth, low birth weight, sex, and a previous fracture barely reduced those risks: 22% increased risk for PPI use, 4% increased risk for H2 blocker use, and 31% increased risk for using both. The vast majority of children who took antacids had been prescribed them in their first 6 months, so the researchers calculated adjusted risk by age of exposure. For H2 blockers, no statistically significant increased risk of fracture existed in those taking them before or after 6 months old.

Those taking PPIs, however, had a 25% increased risk of fracture if they took them before 6 months old, compared with a 20% increased risk if prescribed PPIs between 6 and 12 months. Likewise, children taking both PPIs and H2 blockers before 6 months old had a 32% increased risk of fracture, compared with a 23% increased risk between 6 and 12 months old.

Analysis of the duration of children’s use of antacids revealed a dose-response relationship, with an increasing risk alongside increasing days taking the medication. For example, those on PPIs for a month or less had a 19% increased risk of fracture, compared with children not prescribed antacids, but that rose to a 23% increased risk for those taking PPIs from 60 to 150 days and to a 42% increased risk for taking them longer than 150 days.

Similarly, the risk of fracture after having taken H2 blockers for up to a month was 14%, which increased to 22% for medication durations over 120 days. Children on combination therapy took the medication for much longer than did children prescribed either antacid. The risk of fracture was 17% greater for those taking them for up to 4 months, but that increased to a 50% greater risk for children taking both antacids for longer than 338 days.

“A couple of decades ago, we thought these medications were super safe, that there could be no problem with them,” Dr. Malchodi said, suggesting that their availability over the counter for adults may contribute to that perception. “With this growing evidence, there’s at least a lot more caution about using them,” she said.

Because the study relied on prescriptions for antacids, the researchers could not take into account which children actually took the antacids. Another limitation was their inability to consider other potential confounders, such as socioeconomic status or comorbidities that may later increase the risk of fracture. Further, exclusion of 6 months of follow-up after one fracture may have missed new fractures in that time period. Using a military cohort, on the other hand, meant having a geographically and socioeconomically diverse population with less risk of care bias because all the children had universal health care coverage.

No external funding was used. Dr. Malchodi reported having no disclosures.