Water recreation-related spinal injuries: risk factors in natural bodies of water.

Spinal cord injuries are a major public health problem, and costs to society may total $6.2 billion per year. Using a case-control design, we investigated risk factors for spinal injury in male Wisconsin residents who sustained their injuries during water recreational activity. Compared with the controls, the people who sustained spinal injury were more likely to have entered the water from a pier or dock; to have dived into water; and to have used alcohol. Injury prevention programs for water recreation enthusiasts should address the topics of the hazards of combining alcohol with these activities, how to enter natural bodies of water safely, and safe water levels for diving.

A multifocal outbreak of hepatitis A traced to commercially distributed lettuce.

From February 1 through March 20, 1988, 202 cases of hepatitis A were reported in and around Jefferson County, Kentucky. The epidemic curve indicated a common-source exposure. However, there was no apparent single source of exposure from a restaurant, or community gathering; nor was there a geographic clustering by residence. Cases were mainly adults 20-59 years old (89 percent); 51 percent were female. A case-control study using neighborhood controls found that factors associated with hepatitis A were: having eaten downtown (odds ratio [OR] = 4.0) and having dined at any one of three restaurants (OR = 21.0). Case-control studies of patrons of two of these restaurants found that eating green salad was strongly associated with acquiring hepatitis A: OR = 11.6 and OR = 4.4. The three implicated restaurants accounted for 71 percent of the cases. All three restaurants were supplied by the same fresh produce distributor; however, investigation suggested that contamination most likely occurred prior to local distribution. This outbreak of hepatitis A is the first in the United States apparently associated with fresh produce contaminated before distribution to restaurants, and raises important public health issues regarding the regulation of fresh produce.

SMRFIT: a Statistical Analysis System (SAS) program for standardized mortality ratio analyses and Poisson regression model fits in community disease cluster investigations.

Increasingly, health departments are being pressed by the public to respond to disease risk with cluster investigations in communities and neighborhoods. This is a direct result of growing concern about the role that the environment may play in disease risk. While extensive analyses directly inputing exposures or numbers at risk are often necessary to thoroughly investigate clusters, it is quite useful to perform an exploratory analysis with existing morbidity and mortality data as a first level of response. To meet this need for timely evaluation, the authors describe a user-friendly Statistical Analysis System (SAS) program called SMRFIT to automate community disease cluster evaluations. The program creates frequency tables for number at risk and number of disease outcomes for the community, balance of parent county, and balance of state. SMRFIT then constructs standardized mortality ratios, with the community compared with balance of county and balance of state referents. Poisson regression is offered as an option for the modeling of community disease rates.

Liver cancer in Wisconsin: the potential for prevention.

In this study liver cancer deaths that could be attributed to certain risk factors were calculated. Applying population attributable risk methodology, the attributable risk of liver cancer was estimated for alcohol use, hepatitis B viral exposure, and occupational and industrial exposures. We found that these three risk factors accounted for 38% of liver cancer mortality in Wisconsin; 29% was attributable to alcohol consumption, 7% to occupational exposures, and 2% to hepatitis B viral infection. More than half of liver cancer mortality, however, was not accounted for by the three risk factors studied.

Changes in T-lymphocyte distribution associated with ingestion of aldicarb-contaminated drinking water: a follow-up study.

The carbamate pesticide, aldicarb, is the most commonly found man-made groundwater contaminant in Wisconsin. A 1985 study linked ingestion of aldicarb-contaminated drinking water with altered T-cell distributions, specifically an increase in the mean number of CD8+ (T8) T cells. To further evaluate this finding, a follow-up study was done in 1987. Of the 50 Portage County, Wisconsin, women who participated in the first study, 45 participated in the follow-up: 18 formerly exposed and 27 formerly unexposed. In our follow-up study, only 5 women were found to be currently exposed to aldicarb. This group of 5 women, compared to 39 unexposed women who had peripheral blood specimens taken, had an increased percentage of lymphocytes and an increased number of CD2+ T cells, due to an increased number of total CD8+ T cells. Although the number of exposed persons was small, the increases in percentage lymphocytes and absolute numbers of CD2+ and CD8+ T cells were consistent with a dose-response relationship. No identified drinking water contaminant other than aldicarb could explain these findings. These results support earlier evidence linking aldicarb exposure and lymphocyte distribution changes. Although adverse clinical effects have not been documented, the widespread use of this chemical and consequent potential for widespread exposure indicate a clear need for further research on this issue.