As the future of internal medicine weighs heavily on primary care physicians, with many internists seeking brighter pastures and some even predicting the death of primary care, questions concerning the risks and benefits of specific therapies continue to dominate the clinical picture.

One controversy featured in this issue concerns subclinical hypothyroidism. Whereas many physicians simply ignore subclinical disease, others may be overprescribing thyroxine for it. Acknowledging the controversial data, Dr Cooper lists specific populations that warrant screening and often treatment for subclinical disease, emphasizing the risk of progression to overt disease and the potential link to cardiovascular disease. He adds the intriguing observation that in those 85 or older, subclinical levels seem to prolong life.

Noting that the data do not support treating asymptomatic persons, Dr McCue nevertheless contends that treating subclinical disease may help elderly patients feel better, but he questions the wisdom of screening this population for subclinical disease.

Another controversy emerging in this issue is the question of what to do with vitamin D deficiency, an increasing problem in all age-groups. Perhaps not coincidentally, while Americans have gotten used to the idea that protection from the sun is necessary to prevent malignant skin lesions (not to mention that dreaded specter, wrinkles), evidence of vitamin D deficiency among Americans is growing, as is the evidence demonstrating the need for this vitamin.

Every day, it seems, a new study is published that touts another angle of the role this vitamin plays in our health. What remains unknown is whether taking vitamin D supplements, or even following a diet rich in the very few nutrients that supply this vitamin, is at all efficacious.

Several studies in this issue discuss the consequences of vitamin D deficiency. One study, which focuses on the impact of deficiency on elderly persons, is telling physicians to recommend supplementation to their older patients. A second study suggests that although the deficiency is prevalent, whether sun exposure alone, or diet too, can correct this deficiency is not at all clear. The investigators suggest that 25-hydroxyvitamin D, "which is derived mainly from sun exposure and less from nutritional intake", is the type of vitamin D that affects the blood levels, which leads them to question the efficacy of dietary supplementation.

Adding to this confusion, Dr McCue cites a recent study that showed the data for the efficacy of vitamin D and calcium supplementation for the purpose of reducing fractures "are not very strong". But the evidence linking adequate levels of vitamin D with disease prevention is growing.

Results of a third study indicate that this vitamin is associated with a reduced risk of age-related macular degeneration. So while the evidence demonstrates an important role for this vitamin in our health, what to do with those who are deficient remains unclear. As with other vitamins, while their role is becoming clearer, the exact amounts needed to maintain health are becoming fuzzier. Studies are now needed to establish better recommendations based on new data, taking into consideration the level of absorption in different age-groups, as well as in combination with pharmaceuticals.

Another controversial topic is how important are low levels of high-density lipoprotein cholesterol (HDL-C) and whether treatment is at all beneficial. After considering all the evidence, Dr Toth explains why treatment of low HDL-C is appropriate.

Dalia Buffery, Group Editor