Mass mailing and staff experience in a total recruitment program for a clinical trial: the SHEP experience. Systolic Hypertension in the Elderly Program. Cooperative Research Group.

The Systolic Hypertension in the Elderly Program (SHEP) staff contacted 447,921 screenees, of whom 11,919 (2.7%) were originally eligible and 4,736 (1.1%) maintained eligibility and were randomized. The total number of participants enrolled at the 16 clinical centers ranged from 133 to 559. The low yield of screenees to randomizations resulted from the study design, not from low levels of agreement to participate, and required the employment of a variety of recruitment strategies in a prudent overall plan. SHEP was one of the first clinical trials to use mass mailing as a primary strategy of recruitment. The study used mailing lists from seven generic sources. More than 3.4 million letters of invitation were mailed; they yielded an overall response rate of 4.3%. Motor vehicle and voter registration lists provided the greatest numbers of names. Mailings to members of health maintenance organizations (HMOs) and registrants of the Health Care Finance Administration (HCFA) provided the greatest response rates. Considerable variability in response rates existed among clinical centers using generically similar mailing lists. Generally, the number of hours spent on recruitment showed a positive, but not statistically significant, association with randomization yields. The recruitment yield was statistically significantly higher in clinics with experienced recruitment coordinators than in clinics with inexperienced ones (p = 0.0008). From these findings we conclude that mass mailing is an important strategy in an overall recruitment program, that the involvement of experienced recruitment staff is important, and that although the total time spent by staff on recruitment may also improve results, it matters less than the staff's level of recruiting experience.

Clinical report on long-term bone density after short-term EMF application.

A 1984 study determined the effect of a 72 Hz pulsating electromagnetic field (PEMF) on bone density of the radii of post-menopausal (osteoporosis-prone) women, during and after treatment of 10 h daily for 12 weeks. Bone mineral densities of the treated radii increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks. Bone density determination of the radii of these women, remeasured after eight years, suggests no long-term changes. The bone density-enhancing effect of PEMFs should be further studied, alone and in combination with exercise and pharmacologic agents such as the bisphosphonates and hormones, as prophylaxis in the osteoporosis-prone postmenopausal woman and as a possible block to the demineralization effect of microgravity.

Bone density changes in osteoporosis-prone women exposed to pulsed electromagnetic fields (PEMFs).

To determine the effect of a 72 Hz pulsating electromagnetic field (PEMF) on bone density of the radii of osteoporosis-prone women, the nondominant forearms of 20 subjects were exposed to PEMF 10 h daily for a period of 12 weeks. Bone density before, during, and after the exposure period was determined by use of a Norland-Cameron bone mineral analyzer. Bone mineral densities of the treated radii measured by single-photon densitometry increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks. A similar but weaker response occurred in the opposite arm, suggesting a "cross-talk" effect on the nontreated radii, from either possible arm proximity during sleep or very weak general field effects. The data suggest that properly applied PEMFs, if scaled for whole-body use, may have clinical application in the prevention and treatment of osteoporosis.