In an analysis of studies including more than 180,000 subjects, researchers have found that general health checkups — like annual physicals or other visits to the doctor by asymptomatic people — are ineffective and possibly harmful.

The investigators found no evidence that an annual physical will prevent death by cancer, cardiovascular disease or any other cause. Nor did they find any effect on hospital admissions, disability, additional visits to the doctor or absences from work.

The researchers, writing in the October issue of The Cochrane Library, found that health checkups have no effect on clinical events or other measures of morbidity.

The first red flag is that this is a Chochrane Library study. These studies take articles on the subject and put their data into their computers, and voila, instant results if the treatment works.

The problem? Garbage in, garbage out.

Are these studies of young people? Old people? High risk people? Targeted physicals? routine screening?

One item that really raises a red flag is that these were "old" studies. How old? Who knows. Yet "one trial" did find things we can treat and stop the diseases:

But one trial found an increased rate of diagnoses of hypertension and high cholesterol, the scientists noted, and another found a 20 percent increase in the number of new diagnoses per patient.

One possible harm, the authors point out, is that the checkups can lead to unnecessary treatment of conditions that would not cause symptoms or death.

The authors acknowledge that most of the studies are old, which may make the findings less applicable to modern health settings.