Meta-analysis of empirical evidence on biodiversity and the risk of asthma.

What was studied

This meta-analysis pooled studies on biodiversity and asthma. It looked at biodiversity in the environment and in the human microbiota. The team asked if exposure links to asthma. They used standardized mean differences and relative risks.

What they found

Environmental biodiversity, measured with the Shannon index, showed no clear link to asthma. Higher bacterial richness showed a protective link with asthma. For human microbiota, high bacterial diversity went with asthma risk in one estimate. High richness did too. An estimate based on odds ratios was not significant.

What it means for patients

The authors say links between biodiversity and asthma are variable. They say direction and size depend on the measure and method used. They say this holds for both environment and microbiota exposure. The abstract calls the overall picture variable.

Why it is not certain yet

The abstract notes considerable heterogeneity across the studies. It also notes publication bias. Results varied with the method used. The abstract does not say how the studies were rated. The abstract does not give the number of studies or people. The abstract gives no figures for the size of the links.

Source

Meta-analysis of empirical evidence on biodiversity and the risk of asthma.

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