Biomedical subjects

Thomas Sinks

Publications and source records attributed to Thomas Sinks.

6 recordsLinked to original sources

PubMed2006

Health effects of hazardous waste.

Since 1995, the Agency for Toxic Substances and Disease Registry (ATSDR) has evaluated environmental contaminants and human health risks at nearly 3000 sites. Hazardous substances at these sites include newly emerging problems as well as historically identified threats. ATSDR classifies sites according to the degree of hazard they represent to the public. Less than 1% of the sites investigated are considered urgent public health hazards where chemical or physical hazards are at levels that could cause an immediate threat to life or health. Approximately 20% of sites have a potential for long-term human exposures above acceptable risk levels. At almost 40% of sites, hazardous substances do not represent a public health hazard. Completed exposure pathways for contaminants in air, water, and soil have been reported at approximately 30% of evaluated sites. The most common contaminants of concern at these sites include heavy metals, volatile organic compounds, and polychlorinated biphenyls. This article reviews ATSDR's ongoing work by examining the historic hazard of lead, the contemporary hazard of asbestos, and the emerging issue of perchlorate contamination.

Asbestos↗

PubMed2006

Blood lead concentrations in children and method of water fluoridation in the United States, 1988-1994.

Some have hypothesized that community water containing sodium silicofluoride and hydrofluosilicic acid may increase blood lead (PbB) concentrations in children by leaching of lead from water conduits and by increasing absorption of lead from water. Our analysis aimed to evaluate the relation between water fluoridation method and PbB concentrations in children. We used PbB concentration data (n=9,477) from the Third National Health and Nutrition Examination Survey (1988-1994) for children 1-16 years of age, merged with water fluoridation data from the 1992 Fluoridation Census. The main outcome measure was geometric mean PbB concentration, and covariates included age, sex, race/ethnicity, poverty status, urbanicity, and length of time living in residence. Geometric mean PbB concentrations for each water fluoridation method were 2.40 microg/dL (sodium silicofluoride), 2.34 microg/dL (hydrofluosilicic acid), 1.78 microg/dL (sodium fluoride), 2.24 microg/dL (natural fluoride and no fluoride), and 2.14 microg/dL (unknown/mixed status). In multiple linear and logistic regression, there was a statistical interaction between water fluoridation method and year in which dwelling was built. Controlling for covariates, water fluoridation method was significant only in the models that included dwellings built before 1946 and dwellings of unknown age. Across stratum-specific models for dwellings of known age, neither hydrofluosilicic acid nor sodium silicofluoride were associated with higher geometric mean PbB concentrations or prevalence values. Given these findings, our analyses, though not definitive, do not support concerns that silicofluorides in community water systems cause higher PbB concentrations in children. Current evidence does not provide a basis for changing water fluoridation practices, which have a clear public health benefit.

Adolescent↗

PubMed2004

Hair mercury levels in U.S. children and women of childbearing age: reference range data from NHANES 1999-2000.

Exposure to methyl mercury, a risk factor for neurodevelopmental toxicity, was assessed in U.S. children 1-5 years of age (n = 838) and women 16-49 years of age (n = 1,726) using hair mercury analysis during the 1999-2000 National Health and Nutrition Examination Survey (NHANES). The data are nationally representative and are based on analysis of cross-sectional data for the noninstitutionalized, U.S. household population. The survey consisted of interviews conducted in participants' homes and standardized health examinations conducted in mobile examination centers. Distributions of total hair mercury levels expressed as micrograms per gram hair Hg and the association of hair Hg levels with sociodemographic characteristics and fish consumption are reported. Geometric mean (standard error of the geometric mean) hair mercury was 0.12 microg/g (0.01 microg/g) in children, and 0.20 microg/g (0.02 microg/g) in women. Among frequent fish consumers, geometric mean hair mercury levels were 3-fold higher for women (0.38 vs. 0.11 micro g/g) and 2-fold higher for children (0.16 vs. 0.08 microg/g) compared with nonconsumers. The NHANES 1999-2000 data provide population-based data on hair mercury concentrations for women and children in the United States. Hair mercury levels were associated with age and fish consumption frequency.

Adolescent↗

PubMed2003

Organic mercury levels among the Yanomama of the Brazilian Amazon Basin.

The Catrimani River basin in northern Brazil is the home of the Yanomama and has been the site of renegade gold mining since 1980. Gold-mining operations release inorganic mercury (Hg) into the environment where it is organified and biomagnified in aquatic ecosystems. Ingestion of mercury-contaminated fish poses a potential hazard to fish-eating populations such as the Yanomama. We surveyed Hg levels in Yanomama villagers living near mined and unmined rivers in 1994 and 1995, and analyzed Hg levels in piranha caught by villagers. In 1994, 90 Yanomama Indians from 5 villages and in 1995, 62 Yanomama Indians from 3 villages participated in the studies. Four villages surveyed in 1994 were located directly on the Catrimani River, approximately 140-160 km downstream from past gold-mining activities. The other village surveyed in 1994 was situated on the unmined Ajaraní River. In 1995, 2 of the Catrimani River villages were revisited, and a third Yanomama village, on the unmined Pacu River, was surveyed. Blood organic mercury levels among all villagers surveyed ranged from 0 to 62.6 microg L(-1) (mean levels in each village between 21.2 microg L(-1) and 43.1 microg L(-1)). Mercury levels in piranha from the mined Catrimani River ranged from 235 to 1084 parts per billion (ppb). Nine of 13 piranhas, measuring 30 cm or longer had total mercury levels which exceeded mercury consumption limits (500 ppb) set by both the World Health Organization and the Brazilian Ministry of Health. Unexpectedly, high mercury levels were also observed in fish and villagers along the unmined Ajaraní and Pacu Rivers suggesting that indirect sources may contribute to environmental mercury contamination in the Amazon basin.

Adolescent↗

PubMed2002

Things to know and do about cancer clusters.

Perceived cancer clusters present difficulties and opportunities for clinicians and public health officials alike. Public health officials receive reports of perceived cancer clusters, evaluate the validity of these reports, and/or launch investigations to identify potential causes. Clinicians interact directly with the affected patients, families, or community representatives who question the occurrence of cancer and the underlying causes. Clinicians may identify cancer clusters when they question the unusual occurrence of a rare form of cancer within their practice or community. In addition, clinicians may be asked to discuss cancer clusters and inform local debates. In this paper, we describe the public health practice experience with cancer clusters and identify cancer prevention and control opportunities for clinicians and public health officials. Scientific investigations of cancer clusters rarely uncover new knowledge about the causes of cancer. However, a set of common characteristics, unique to etiologic cluster investigations have uncovered new information about the causes of cancer or demonstrated a preventable link to a known carcinogen. These characteristics may provide useful clues for sorting out the small number of clusters worthy of further scientific investigation. Public awareness of cancer clusters may promote an opportunity to inform and motivate people about the preventable causes of cancer and effective cancer screening methods.

Cluster Analysis↗

PubMedDate not supplied

Understanding cancer clusters.

Each year, state and local health departments respond to more than 1,000 inquiries about suspected cancer clusters. Three quarters of these reports involve situations that are clearly not clusters and can be resolved by telephone. For the remainder, follow-up is needed, first to confirm the number of persons affected, their age, type of cancer, dates of diagnosis, and other factors, and then to compare cancer incidence in the affected population with background rates in state tumor registries. In approximately 5% to 15% of the reported situations, formal statistical testing confirms that the number of observed cases exceeds the number expected in a specific area, given the age, sex, and size of the affected population. Even in these instances, however, chance remains a plausible explanation for many clusters, and further epidemiologic investigation almost never identifies the underlying cause of disease with confidence. The few exceptions have involved clusters of extremely rare cancers occurring in well-defined occupational or medical settings, generally involving intense and sustained exposure to an unusual chemical, occupation, infection, or drug. This article discusses the resources and scientific tools currently available to investigate cancer clusters. It also provides a framework for understanding cancer clusters and a realistic appraisal of what cluster investigations can and cannot provide in the context of community expectations.

Cluster Analysis↗