Relation between policies and work related assault: Minnesota Nurses' Study.

AIMS: To assess the relation between violence prevention policies and work related assault. METHODS: From Phase 1 of the Minnesota Nurses' Study, a population based survey of 6300 Minnesota nurses (response 79%), 13.2% reported experiencing work related physical assault in the past year. In Phase 2, a case-control study, 1900 nurses (response 75%) were questioned about exposures relevant to violence, including eight work related violence prevention policy items. A comprehensive causal model served as a basis for survey design, analyses, and interpretation. Sensitivity analyses were conducted for potential exposure misclassification and the presence of an unmeasured confounder. RESULTS: Results of multiple regression analyses, controlling for appropriate factors, indicated that the odds of physical assault decreased for having a zero tolerance policy (OR = 0.5, 95% CI 0.4 to 0.8) and having policies regarding types of prohibited violent behaviours (OR = 0.5, 95% CI 0.3 to 0.9). Analyses adjusted for non-response and non-selection resulted in wider confidence intervals, but no substantial change in effect estimates. CONCLUSIONS: It appears that some work related violence policies may be protective for the population of Minnesota nurses.

An epidemiological study of the magnitude and consequences of work related violence: the Minnesota Nurses' Study.

AIMS: To identify the magnitude of and potential risk factors for violence within a major occupational population. METHODS: Comprehensive surveys were sent to 6300 Minnesota licensed registered (RNs) and practical (LPNs) nurses to collect data on physical and non-physical violence for the prior 12 months. Re-weighting enabled adjustment for potential biases associated with non-response, accounting for unknown eligibility. RESULTS: From the 78% responding, combined with non-response rate information, respective adjusted rates per 100 persons per year (95% CI) for physical and non-physical violence were 13.2 (12.2 to 14.3) and 38.8 (37.4 to 40.4); assault rates were increased, respectively, for LPNs versus RNs (16.4 and 12.0) and males versus females (19.4 and 12.9). Perpetrators of physical and non-physical events were patients/clients (97% and 67%, respectively). Consequences appeared greater for non-physical than physical violence. Multivariate modelling identified increased rates for both physical and non-physical violence for working: in a nursing home/long term care facility; in intensive care, psychiatric/behavioural or emergency departments; and with geriatric patients. CONCLUSIONS: Results show that non-fatal physical assault and non-physical forms of violence, and relevant consequences, are frequent among both RNs and LPNs; such violence is mostly perpetrated by patients or clients; and certain environmental factors appear to affect the risk of violence. This serves as the basis for further analytical studies that can enable the development of appropriate prevention and control efforts.

The effect of fecal occult-blood screening on the incidence of colorectal cancer.

BACKGROUND: Both annual testing for fecal occult blood and biennial testing significantly reduce mortality from colorectal cancer. However, the effect of screening on the incidence of colorectal cancer remains uncertain, despite the diagnosis and removal of precancerous lesions in many persons who undergo screening. METHODS: We followed the participants in the Minnesota Colon Cancer Control Study for 18 years. A total of 46,551 people, most of whom were 50 to 80 years old, were enrolled between 1975 and 1978 and randomly assigned to annual screening, biennial screening, or usual care (the control group). Those assigned to the screening groups were asked to prepare and submit two samples from each of three consecutive stools for guaiac-based testing. Those with at least one positive slide in the set of six were offered a diagnostic examination that included colonoscopy. Screening was conducted between 1976 and 1982 and again between 1986 and 1992. Study participants have been followed with respect to newly diagnosed cases of colorectal cancer and deaths. Follow-up has been more than 90 percent complete. RESULTS: During the 18-year follow-up period, we identified 1359 new cases of colorectal cancer: 417 in the annual-screening group, 435 in the biennial-screening group, and 507 in the control group. The cumulative incidence ratios for colorectal cancer in the screening groups as compared with the control group were 0.80 (95 percent confidence interval, 0.70 to 0.90) and 0.83 (95 percent confidence interval, 0.73 to 0.94) for the annual-screening and biennial-screening groups, respectively. For both screening groups, the number of positive slides was associated with the positive predictive value both for colorectal cancer and for adenomatous polyps at least 1 cm in diameter. CONCLUSIONS: The use of either annual or biennial fecal occult-blood testing significantly reduces the incidence of colorectal cancer.

Colorectal cancer deaths as determined by expert committee and from death certificate: a comparison. The Minnesota Study.

For deaths during the first 13 years of follow-up of the Minnesota Colon Cancer Control Study, an expert committee using numerous medical documents, and a nosologist using only the death certificate independently determined whether colorectal cancer caused the death and, if not, whether the disease was present at death. Deaths due to colorectal cancer numbered 318 according to the nosologist and 323 according to the committee, a discrepancy of 1.5%, which is similar in magnitude to that in three previous studies. The nosologist and committee agreed that colorectal cancer caused the death in each of 290 individual cases; they disagreed widely on the number of deaths from other causes but with colorectal cancer. If it is important to know only the gross number of deaths from colorectal cancer, then the death certificate alone appears to be sufficiently accurate; if it is important to know the cause of death of individual subjects or the number dying from other causes but with colorectal cancer, then the expert committee method provides more accurate information.

Longitudinal compliance with annual screening for fecal occult blood. Minnesota Colon Cancer Control Study.

In a randomized, controlled trial of fecal occult blood screening for colorectal cancer, the Minnesota Colon Cancer Control Study carried out 11 annual mail screens in two phases between 1976 and 1992. This long-term compliance record of 15,476 individuals is summarized and related to demographic characteristics as well as to the screening experience of the participants. There was a strong and consistent effect of age, with peak compliance among participants about 70 years old, and lower compliance among the youngest (< or = 55 years) and oldest (> or = 80 years) participants. There was a significantly higher rate of screen compliance among participants who lived with other participants, compared with households where only one individual participated in the study. Finally, participants who underwent a diagnostic colorectal examination with negative results had significantly lower odds of compliance.

Estimating the duration of ongoing prevention trials.

The authors present a method of estimating the duration of ongoing prevention trials, showing how the method was applied to the Colon Cancer Control Study, a University of Minnesota study of occult blood testing undertaken to screen for colorectal cancer in older Minnesotans. In that study, begun in 1975 and ongoing, as in several other recent large prevention trials, it was necessary, after the start of the study, to revise upward the initial estimates of study duration derived from general population experience. The underestimates arose because the planners had not adequately taken various population selection factors into account in estimating the expected number of events in the control group. In this paper, the authors outline a method for estimating control group event rates and study duration requirements (and, in some circumstances, also sample size requirements) of prevention studies, via models of disease-specific and all-cause standardized mortality ratios which adjust for various selection effects. The authors also validate the model for disease-specific standardized mortality ratios by means of independent estimates of disease incidence and case survival.

C-peptide response to meal challenge in nondiabetic and diabetic adults living in Wadena, Minnesota.

OBJECTIVE: The goal of the study was to provide cross-sectional descriptive data on the response of C-peptide to a vigorous meal stimulus in a population-based sample of nondiabetic adults compared with a population-based sample of adults with NIDDM. Available information is scanty, especially in subjects greater than 50 yr old. RESEARCH DESIGN AND METHODS: The group under study included 377 adults without previously known diabetes randomly chosen from the population of the city of Wadena, Minnesota, almost all of northern European background, and 88 adults with known diabetes. PCP was measured 90 min after ingestion of 480 ml liquid meal Ensure-Plus, which includes 95 g dextrose, 26 g protein, and 25 g fat. C-peptide also was measured in a 260-min urine collection after the meal challenge. Novo antibody M1221 was used for C-peptide assay throughout the study. Participants whose medical record indicated insulin-dependent diabetes with a history of acetone production were excluded from analyses. RESULTS: The distribution of UCP and PCP in this group of subjects appears very broad. Both the highest and lowest values for C-peptide were observed in individuals with diabetic glucose tolerance. The mean and median values in the nondiabetic group are higher than in previously published reports. After statistical adjustment for age, sex, BMI, and concomitant plasma glucose, participants with IGT produced significantly more C-peptide than the group with NGT (3.48 vs. 2.96 nM PCP, P less than 0.05). Participants with diabetic glucose tolerance and who were not taking insulin produced as much or more C-peptide than either the NGT or IGT groups, depending on the statistical model used for adjusting for plasma glucose. Diabetic participants who were taking insulin produced significantly lower amounts of C-peptide than any of the non-insulin-taking groups (approximately 30% of the C-peptide produced by the non-insulin-taking diabetic participants). A decline in PCP production with increasing years since diagnosis (5.7%/yr) was observed exclusively in the insulin-taking NIDDM participants. Effect modification by glucose tolerance classification was observed on the relationship between plasma glucose and PCP: PCP increased with increasing plasma glucose in NGT and IGT groups, but a nonsignificant negative relationship was exhibited in diabetic participants. CONCLUSIONS: The data suggest that two forms of NIDDM may exist, crudely distinguished by the clinical decision to use insulin to control blood glucose levels. The insulin-taking diabetic individuals may experience a greater likelihood of pancreatic failure, whereas non-insulin-taking diabetic individuals probably experience stable pancreatic function over the course of their disease. Longitudinal observation of the Wadena cohort will provide more insight into this possibility.