We’d like to explain why this study is nonsense, but of course that’s difficult to do with science-by-press-release-and abstract.
Here’s the text of the media release:
Low-fat yogurt intake when pregnant may lead to child asthma and hay fever
Amsterdam, The Netherlands: Eating low-fat yoghurt whilst pregnant can increase the risk of your child developing asthma and allergic rhinitis (hay fever), according to recent findings.
The study will be presented at the European Respiratory Society’s (ERS) Annual Congress in Amsterdam on 25 September 2011. All the abstracts for the ERS Congress will be publicly available online from today (17 September 2011).
The study aimed to assess whether fatty acids found in dairy products could protect against the development of allergic diseases in children.
The researchers assessed milk and dairy intake during pregnancy and monitored the prevalence of asthma and allergic rhinitis using registries and questionnaires in the Danish National Birth Cohort.
The results showed that milk intake during pregnancy was not associated with increased risk of developing asthma and it actually protected against asthma development. However, women who ate low-fat yoghurt with fruit once a day were 1.6-times more likely to have children who developed asthma by age 7, compared with children of women who reported no intake. They were also more likely to have allergic rhinitis and to display current asthma symptoms.
The researchers suggest that non-fat related nutrient components in the yoghurt may play a part in increasing this risk. They are also looking at the possibility that low-fat yoghurt intake may serve as a marker for other dietary and lifestyle factors.
Ekaterina Maslova, lead author from the Harvard School of Public Health, who has been working with data at the Centre for Fetal Programming at Statens Serum Institut, said: “This is the first study of its kind to link low-fat yoghurt intake during pregnancy with an increased risk of asthma and hay fever in children. This could be due to a number of reasons and we will further investigate whether this is linked to certain nutrients or whether people who ate yoghurt regularly had similar lifestyle and dietary patterns which could explain the increased risk of asthma.”
Here’s the abstract:
Body: Background: Dairy products are important sources of micronutrients, fatty acids, and probiotics that could modify the risk of child asthma and allergy development.
Objective: To examine associations of dairy intake during pregnancy with child asthma and allergic rhinitis (AR) at 7 years in the Danish National Birth Cohort.
Methods: Data on milk and yoghurt consumption was collected in mid-pregnancy using a validated FFQ (N=61,912). We assessed asthma and AR through questionnaires and registry linkages. Current asthma was defined as self-reported asthma diagnosis and wheeze in the past 12 months. We conducted multiple logistic regression and report here odds ratios with 95% CI.
Results: At 7 years 5.9% (N=2,316/39,059) of children had registered life-time asthma diagnosis and 4.2% (N=1,574/37,347) reported current asthma. Life-time AR diagnosis was 0.5% (N=191/39,059) using the registry and 4.9% (N=1,887/38,763) by self-report. Total milk intake was inversely related to current asthma risk (>5 glasses/d vs. 0 glasses/d: 0.78, 95% CI: 0.61, 0.98). For yoghurt, children of women who ate low-fat yoghurt (with fruit) >=1 time/day had 1.61 (95% CI: 1.22, 2.12) greater odds of a registry-based asthma diagnosis compared to children of women reporting no intake. They were also more likely to have a registry-based AR diagnosis (2.82, 95% CI: 1.44, 5.53) and to report current asthma (1.62, 95% CI: 1.17, 2.24).
Conclusion: Low-fat yoghurt intake was directly related to increased risk of both child asthma and AR, while total milk intake appeared to be protective. Non-fat related nutrient components in yoghurt may be mediating this increase in risk.
As these are weak and uncertain correlations, we’d like to know more about the obviously self-reported yogurt consumption data and the potential confoudning risk factors for asthma/hay fever. Then there are the mysterious “non-fat related nutrient components” in yogurt and the biological plausibility on causing asthma via maternal diet.
So many questions; so little information to go on. But publish and scare first; study and reason later.