They actually controlled for the possible variability in self-reported illnesses by using biomarkers in the patients, meaning that they could objectively measure whether a patient had a particular illness or not. There are different biomarkers used for different diseases, each with their own sensitivity, and I didn't look to see which they used, but the self-reporting factor is controlled for in this study.
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They actually controlled for the possible variability in self-reported illnesses by using biomarkers in the patients, meaning that they could objectively measure whether a patient had a particular illness or not. There are different biomarkers used for different diseases, each with their own sensitivity, and I didn't look to see which they used, but the self-reporting factor is controlled for in this study.