Stop testing vitamin D in well adults, and why a health-worker programme did not prevent diabetes

The edition in brief

Today's family medicine edition opens with a pragmatic cluster-randomised trial from two New York primary care systems: a 12-month community health worker programme for adults with prediabetes (HbA1c 5.7–6.4%) did not reduce new diabetes (5.9% vs 4.3%) or improve HbA1c, weight, blood pressure or lipids. It did increase primary care visits, and emergency visits too. A UK qualitative study in the British Journal of General Practice (29 October) interviewed patients, clinical pharmacists and GPs about polypharmacy reviews and found unclear case-finding, unclear purpose and a gap between patients' and clinicians' priorities; protocol reviews handled simple problems, but complex cases needed continuity and trust. A small Family Practice feasibility study (6 October) found a timed 28-metre corridor walk was quick, repeatable and acceptable for measuring walking speed in a diabetes clinic. The pearl is the follow-up that prediabetes needs. The practice changer is an American Family Physician review (1 October) of the vitamin D evidence: there is no support for screening or supplementing community-dwelling adults, whatever their baseline level. Randomised trials show no reduction in death, cardiovascular disease, falls, fractures, cancer, dementia, infections or depression, and no reliable relief of fatigue, hair loss or chronic pain. A recommended daily intake of 600 IU up to age 70 and 800 IU after that keeps almost everyone above deficiency. Selected people with prediabetes may benefit from several years of higher-dose supplementation. Testing remains appropriate where there is a clinical reason, such as malabsorption or bone disease.