Plasma amyloid beta (Abeta42) levels increase with age and are elevated in some patients during the early stages of Alzheimer's disease (AD). Although plasma Abeta42 is not useful for diagnosis of AD, it might be a biological risk factor. In the elderly population a considerable variety of concomitant medication is used for the treatment of various disorders. How this co-medication might influence Abeta42 levels is still to be investigated. Through the Vienna Transdanube Aging study (VITA), the authors measured cross-sectional Abeta42 plasma levels during the initial examination of 526 individuals aged 75 years without dementia. The medication considered included: treatment with calcium channel blockers, digitalis, anticoagulants, antihistamines, ergotamine, histamine H(2) receptor antagonists, bronchodilators, pentoxyfilline, neuroleptics, insulin, oral antidiabetics, l-dopa, benzodiazepines, oestrogen, Gingko biloba, vitamins, piracetam, non-steroidal anti-inflammatory drugs (NSAIDs), and statins. Of the study population aged 75 years, 90% were users of some of the above-mentioned medication. Depending on their medial temporal lobe atrophy (MTA), users of insulin showed significantly increased levels of Abeta42, while users of gingko biloba for at least 2 years of drug intake had significantly decreased Abeta42 plasma levels, independent of their MTA. Users of NSAIDs showed a non-significant trend to reduced Abeta42 plasma levels, while users of biguanides showed an increase in Abeta42 plasma levels. In the multiple regression analysis considering possible interactions between various medications statin users showed a significant decrease of Abeta42; insulin users had again significantly higher and long-term gingko biloba users lower plasma Abeta42 levels. Persons with a low degree of MTA had significantly increased Abeta42 plasma levels. Considering the increase of Abeta42 plasma levels as a risk factor for AD, any changes induced by medication by long-term use in the peripheral and possibly also in the central compartment, could be of clinical relevance.