Prenatal, Early Sugary Drink Exposure Ups Asthma Risk in Kids

Diana Phillips

December 15, 2017

Children of mothers who drink large amounts of sugary beverages during pregnancy and those with high dietary intake of fructose in early childhood may be at increased risk of developing asthma in midchildhood, according to the findings of a study published online December 8 in the Annals of the American Thoracic Society.

In addition, the relationship between in utero and early childhood exposure to the sweeteners and later asthma appears to be independent of children's adiposity, Lakiea S. Wright, MD, from Harvard Medical School and the Division of Rheumatology, Immunology, and Allergy, Department of Medicine, at Brigham and Women's Hospital, Boston, Massachusetts, and colleagues report.

Links between obesity and overweight and both asthma and fructose consumption have been previously established, and "[r]ecent studies suggest that in addition to influencing asthma through increasing the risk of obesity, high fructose intake may influence the risk of lung diseases at least in part through distinct mechanisms," the authors write. "Specifically, it has been hypothesized that excess free fructose increases intestinal formation and absorption of advanced glycation end products, which may interact with the receptor of advanced glycation end products, a potential mediator of obstructive lung disease development."

In addition to the association between asthma development and sugar exposure in early childhood, previous data also indicate a relationship between maternal consumption of free sugar during pregnancy and atopy and atopic asthma in midchildhood, according to the authors. On the basis of these multiple associations, they hypothesized that these exposures "during critical periods of lung and immune growth and development" may increase asthma risk.

To test this hypothesis, the researchers analyzed data from 1068 mother–child pairs enrolled in Project Viva, a longitudinal research study looking at the effects of mothers' diet as well as other factors during pregnancy and after birth, between 1999 and 2002.

The researchers gathered data on maternal beverage consumption during pregnancy via food frequency questionnaires completed by the mothers after in-person research visits at the end of their first and second trimesters of pregnancy. The researchers obtained information on early childhood fructose consumption from regular soda and fruit drinks and asthma status, respectively, from questionnaires the mothers completed when their children reached a median 3.3 years, and again at a median 7.7 years.

The investigators used the responses to compute fructose intake, and they analyzed results based on quartiles of sugary beverage and fructose consumption.

Of the child cohort, 19% had asthma at midchildhood and 12% were obese, defined as a body mass index (BMI) at or above the 95th percentile for age and sex. The mean BMI z-score was 0.37 (standard deviation [SD], 0.99).

The mean consumption of fructose by mothers during pregnancy and by children during early childhood was 32.5 (SD, 10.2) g/day and 27.8 (SD, 11.6) g/day, respectively. Among the mothers, the largest beverage source of fructose was citrus juice, whereas noncitrus juice was the largest source for children. "In the highest quartile of fruit juice consumption in our cohort, children were drinking a mean of 3.9 servings (range 3 to 10 servings) per day," they state, noting that the American Academy of Pediatrics recommends consumption of no more than one to two servings per day of fruit juice for children 1 to 6 years old.

Younger mothers; those with less education, lower incomes, and higher prepregnancy BMI; and those of nonwhite race or ethnicity were more likely to have higher intake of sugary drinks.

After adjusting for prepregnancy and other covariates, the analysis of midchildhood asthma risk was more likely for offspring of mothers in quartile 4 (highest) for maternal pregnancy intake of sugar-sweetened drinks (odds ratio [OR], 1.70; 95% confidence interval [CI], 1.08 - 2.67) and total fructose (OR, 1.58; 95% CI, 0.98 - 2.53) compared with those in quartile 1.

Also, higher early childhood fructose intake (quartile 4 vs quartile 1) was associated with midchildhood current asthma after adjusting for maternal intake of sweetened beverages (OR, 1.79; 95% CI, 1.07 - 2.97) and for midchildhood BMI z-score (OR, 1.77; 95% CI, 1.06 - 2.95).

The researchers conducted supplementary analyses to identify possible systemic inflammatory mechanisms underlying the link between intake of beverages with high levels of sugar and fructose and asthma risk. "We...did not find associations of maternal prenatal or early childhood intake of sugar sweetened beverages, juice, and total fructose with peripheral blood levels of [high sensitivity C-110 reactive protein, interleukin 6, and tumor necrosis factor receptor 2] measured in the children at the mid-childhood visit," they write. They note, however, that inflammatory influences may have occurred locally in the lung rather than systemically or at a time outside their measurements. As such, "the absence of association [of] prior intake of fructose with these systemic markers years later does not exclude the possibility that fructose had caused innate cytokine/adipokine-mediated inflammation specific to the airways."

This study "provides additional support for the likelihood that diet and its metabolic effects play an important role in disease risk, even for conditions like asthma," according to Jason E. Lang, MD, associate professor in the Division of Allergy, Immunology and Pulmonary Medicine, Duke University of Medicine, Durham, North Carolina. "We already know that high sugar-sweetened beverage consumption is associated with high blood sugars and insulin resistance, and these metabolic problems have clearly been associated with reactive airways and symptoms of asthma. It's very possible that a mother's consumption of sugary beverages during pregnancy and also a young child's early consumption can both add to the risk of early asthma."

Dr Lang's clinical and translational research interests include the association among diet, obesity, and asthma in children; he was not involved in the study.

Although these study findings are consistent with this hypothesis, "this work in isolation is not sufficient to come to this conclusion since it was an observational study and did not look at intermediate metabolic measures," Dr Lang told Medscape Medical News.

Together with other findings, these data "should be considered when developing recommendations regarding consumption and availability of these drinks during pregnancy and early childhood," the authors state. "Further evaluation of potential mechanisms for influences [of] total fructose [on] asthma development is warranted, including further assessment of effects of fructose and fructose metabolites on airway inflammation or hyper-reactivity that may be independent of obesity."

This study was supported by the National Institutes of Health. The authors and Dr Lang have disclosed no relevant financial relationships.

Ann Am Thoracic Soc. Published online December 8, 2017. Abstract

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