Even moderate weight gain can increase a woman's risk of suffering symptoms of gastro-oesophageal reflux disease (GORD), US researchers have found.

"Overweight and obese persons are at increased risk for GORD," explain Dr Brian Jacobson, from Boston University Medical Center in Massachusetts, and colleagues in the New England Journal of Medicine.

However, they add: "An association between body mass index (BMI) – the weight in kilograms divided by the square of the height in metres – and symptoms of GORD in persons of normal weight has not been demonstrated."

To investigate, the researchers surveyed more than 10,000 women about their weight, weight gain and symptoms of GORD, such as acid reflux and heartburn.

As expected, the researchers found a significant association between being overweight (a BMI of 25 kg/m² or higher) or obese (a BMI of 30 kg/m² or higher) and experiencing GORD symptoms.

They note that heavier women who were considered to have a healthy BMI (between 19 kg/m² and 24 kg/m²) were more likely to experience GORD symptoms than lighter women who also had a healthy BMI.

Moreover, an increase in BMI of 3.5 kg/m, even if the initial BMI was within the healthy range, was associated with around a three-fold increased risk of suffering frequent reflux symptoms.

Dr Jacobson and team conclude: "Our findings suggest that the risk of symptoms of GORD rises progressively with increasing BMI, even among normal-weight persons. This seems true for all degrees of severity and duration of symptoms, as well as for nocturnal symptoms."

They add: "Our findings have important implications for future studies, since even moderate weight gain may cause or exacerbate symptoms of GORD."