Brown tumour of the wrist with primary hyperparathyroidism.

Employers commonly use adjustments to health insurance premiums as incentives to encourage healthy behavior, but the effectiveness of those adjustments is controversial. We gave 197 obese participants in a workplace wellness program a weight loss goal equivalent to 5 percent of their baseline weight. They were randomly assigned to a control arm, with no financial incentive for achieving the goal, or to one of three intervention arms offering an incentive valued at $550. Two intervention arms used health insurance premium adjustments, beginning the following year (delayed) or in the first pay period after achieving the goal (immediate). A third arm used a daily lottery incentive separate from premiums. At twelve months there were no statistically significant differences in mean weight change either between the control group (whose members had a mean gain of 0.1 pound) and any of the incentive groups (delayed premium adjustment, -1.2 pound; immediate premium adjustment, -1.4 pound; daily lottery incentive, -1.0 pound) or among the intervention groups. The apparent failure of the incentives to promote weight loss suggests that employers that encourage weight reduction through workplace wellness programs should test alternatives to the conventional premium adjustment approach by using alternative incentive designs, larger incentives, or both.