Provided are: a marker having a strong correlation with existing markers for metabolic syndrome and lifestyle diseases in a wide range of subjects including specified test subjects between 40 and 74 years of age; and an effective detection method for metabolic syndrome and/or lifestyle diseases. The problem can be solved by the detection method for metabolic syndrome and/or lifestyle diseases, said detection method being characterized by including a step for measuring choline plasmalogen concentration in a test sample.
