Edward L. Baker

Risk factors for Alzheimer's disease A case‐control study

A case-control study was conducted to assess personal and family medical history and the appearance of Alzheimers disease. We compared 98 men with clinically diagnosed Alzheimers disease and 162 controls, matched by sex, year of birth, and town of residence. Family history of dementia and personal history of depression were more frequent in patients. The number of cigarettes smoked was geater in cases.

EPIDEMIC MALATHION POISONING IN PAKISTAN MALARIA WORKERS

In 1976, epidemic organophosphate insecticide poisoning due to malathion occurred among 7500 field workers in the Pakistan malaria control programme. In July, the peak month of the epidemic, it is estimated that there were about 2800 cases. In field studies low red-cell cholinesterase activities were associated with the signs and symptoms of organophosphate insecticide intoxication. Toxicity was seen with 3 different formulations of the insecticide and was greatest with the products containing increased amounts of isomalathion, a toxic malathion degradation product. Poor work practices, which had developed when D.D.T. was the primary insecticide for malaria control, resulted in excessive skin contact with and percutaneous absorption of the pesticide. Airborne malathion concentrations were very low. Implementation of good work practices and proscription of use of the 2 pesticide formulations most contaminated with isomalathion halted the epidemic in September. An extensive training programme and surveillance system for pesticide toxicity preceded 1977 spraying operations.

Increased lead absorption with anemia and slowed nerve conduction in children near a lead smelter

Studies to evaluate the prevalence, sources, and health consequences of lead absorption were conducted among children living near a primary lead smelter. Lead levels in air, soil, and dust were highest at the smelter and decreased with distance. Ninety-nine percent of one- to nine-year-old children living within 1.6 kilometers had blood lead levels greater than or equal 40 mug/dl, indicating increased absorption, and 22% had levels greater than or equal 80 mug/dl. The prevalence of lead levels greater than or equal 40 mug/dl decreased with distance; at 72 kilometers from the smelter it was 1%. Erythrocyte protoporphyrin levels increased with blood lead levels: 17% of children with lead levels of greater than or equal 80 mug/dl were anemic. There was no overt neurologic toxicity. Significant negative correlation was found in 202 five- to nine-year-old children between blood lead levels and motor nerve conduction velocity (r = 0.38, p less than 0.02).

Lead poisoning in children of lead workers: home contamination with industrial dust.

Children may be exposed through various mechanisms to toxins of industrial origin. Contamination of the home environment by soiled work clothing is an important mechanism of such exposure and has b...

Occupational lead poisoning in the United States: clinical and biochemical findings related to blood lead levels.

Dose-response relationships between blood lead levels and toxic effects have been evaluated in 160 lead workers in two smelters and a chemicals plant. Blood lead levels ranged from 0.77 to 13.51 mumol/litre (16-280 microgram/dl). Clinical evidence of toxic exposure was found in 70 workers (44%), including colic in 33, wrist or ankle extensor muscle weakness in 12, anaemia (Hgb less than 8.69 mumol/litre (Hb/4) or 14.0 gm/dl) in 27, elevated blood urea nitrogen (greater than or equal to 7.14 mmol/litre or 20 mg/dl) in 28, and possible encephalopathy in two. No toxicity was detected at blood lead levels below 1.93 mumol/litre (40 microgram/dl). However, 13% of workers with blood lead levels of 1.93 to 3.81 mumol/litre (40-79 microgram/dl) had extensor muscle weakness or gastrointestinal symptoms. Anaemia was found in 5% of workers with lead levels of 1.93-2.85 mumol/litre (40-59 microgram/dl), in 14% with levels of 2.90 to 3.81 mumol/litre (60-79 microgram/dl), and in 36% with levels greater than or equal to 3.86 mumol/litre (80 microgram/dl). Elevated blood urea nitrogen occurred in long-term lead workers. All but three workers with increased blood urea nitrogen had at least four years occupational lead exposure, and nine had received oral chelation; eight of this group had reduced creatinine clearance, and eight had decreased renal concentrating ability. These data support the establishment of a permissible biological limit for blood lead at a level between 1.93 and 2.90 mumol/litre (40-60 microgram/dl).

Availability and Perceived Effectiveness of Public Health Activities in the Nation’s Most Populous Communities

OBJECTIVES We examined the availability and perceived effectiveness of 20 basic public health activities in the communities where most Americans reside. METHODS A self-administered questionnaire was mailed to the 497 directors of US local health departments serving at least 100 000 residents. RESULTS On average, two thirds of the 20 public health activities were performed in the local jurisdictions surveyed, and the perceived effectiveness rating averaged 35% of the maximum possible. In multivariate models, availability of public health activities varied significantly according to population size, socioeconomic measures, local health department spending, and presence of local boards of health. CONCLUSIONS Local public health capacity varies widely across the nations most populous communities, highlighting the need for targeted improvement efforts.

Lead-induced anemia: Dose-response relationships and evidence for a threshold

We conducted a cross-sectional epidemiologic study to assess the association between blood lead level and hematocrit in 579 one to five year-old children living near a primary lead smelter in 1974. Blood lead levels ranged from 0.53 to 7.91 mumol/L (11 to 164 micrograms/dl). To predict hematocrit as a function of blood lead level and age, we derived non-linear regression models and fit percentile curves. We used logistic regression to predict the probability of hematocrit values less than 35 per cent. We found a strong non-linear, dose-response relationship between blood lead level and hematocrit. This relationship was influenced by age, but (in this age group) not by sex; the effect was strongest in youngest children. In one year-olds, the age group most severely affected, the risk of an hematocrit value below 35 percent was 2 percent above background at blood lead levels between 0.97 and 1.88 mumol/L (20 and 39 micrograms/dl), 18 percent above background at lead levels of 1.93 to 2.85 mumol/L (40 to 59 micrograms/dl), and 40 percent above background at lead levels of 2.9 mumol/L (60 micrograms/dl) and greater; background was defined as a blood lead level below 1.88 mumol/L (20 micrograms/dl). This effect appeared independent of iron deficiency. These findings suggest that blood lead levels close to the currently recommended limit value of 1.21 mumol/L (25 micrograms/dl) are associated with dose-related depression of hematocrit in young children.

A review of recent research on health effects of human occupational exposure to organic solvents. A critical review.

The health impact of workplace solvent exposure remains an issue of substantial interest and concern to occupational health professionals. As a result of research performed in the 1970s and 1980s, policies and programs were developed throughout the world to control excessive exposure to solvents. To an extent, these programs have been responsible for reduction of the occurrence of solvent-associated encephalopathy and other health effects. In this review of research performed since 1985, particular attention is given to issues of reversibility of neurotoxicity following exposure cessation. Furthermore, health effects involving other organ systems, particularly reproductive, renal, and hepatic disorders, are discussed. Future research directions are discussed. Finally, the practical implications of these recent research findings are described with a focus on the management of prevention programs at the work site.

Partnership for front-line success: a call for a national action agenda on workforce development.

Despite more than a decade of dialogue on the critical needs and challenges in public health workforce development, progress remains slow in implementing recommended actions. A life-long learning system for public health remains elusive. The Centers for Disease Control and Prevention and the Agency for Toxic Substances and Disease Registry in collaboration with other partners in federal, state, local agencies, associations and academia is preparing a national action agenda to address front-line preparedness. Four areas of convergence have emerged regarding: (1) the use of basic and crosscutting public health competencies to develop practice-focused curricula; (2) a framework for certification and credentialing; (3) the need to establish a strong science base for workforce issues; and (4) the acceleration of the use of technology-supported learning in public health.

Exposure of children to heavy metals from smelters: Epidemiology and toxic consequences☆

Abstract To evaluate the epidemiologic and toxicologic consequences of environmental exposure to heavy metals, we examined populations of children living near 21 primary, nonferrous metal smelters in the United States. At lead smelters in El Paso, Texas, and in Kellogg, Idaho, 59 and 99%, respectively, of 1- through 9-year-old children living within 1.6 km of the smelting plants had blood lead levels ⩾40 μ/dl, indicating greater than normal lead absorption. Children living within 3.2 km of 10 of 11 copper smelters had increased urine arsenic levels, indicating increased systemic absorption of arsenic. Elevated blood cadmium levels were found for children in Bartlesville, Oklahoma, who lived within 3.2 km of a zinc smelter. Biological levels of heavy metals in these populations were related inversely to distance of residence from the smelting plants and were in direct proportion to levels of environmental contamination. Inhalation and ingestion of heavy metal particulates emitted by the smelters into air, soil, and dust were the principal causes of increased absorption. Elevated levels of erythrocyte protoporphyrin, as well as anemia and slowed motor nerve conduction velocity were the dose-related toxic consequences of lead absorption observed in the children studied. These data illustrate the importance of smelters as point sources of heavy metal contamination and as models for epidemiologic study.