A century of epidemiologic transition in the United States.

In the present paper, the theory of the Epidemiologic Transition is applied to describe the population and health dynamics in the United States during the last century. The data presented indicate that the U.S. experience belongs to what is referred to as the “Classical” model. The mortality decline in the U.S. occurred during the latter 19th century and marked a shift from pandemics of infection to degenerative and man-made diseases. The transition favored children more than the old, females more than males, and whites more than nonwhites. Mortality decline in 19th century U.S. owed little to medical progress, sanitation measures, or organized health services. More important determinants were improvements in living standards, personal hygiene, nutrition, housing, and ecologic recession of certain diseases. Fertility in the U.S. started to decline toward the end of the 19th century, a decline that was primarily socially determined. In recent decades, however, the organized element has become visible. The theory of the Epidemiologic Transition can be applied to other populations as well and can be helpful in determining the directions to take in efforts to control population growth. The fact that the theory distinguishes three different models of the transition alerts population students and policymakers to the fallacy of applying the population dynamics and solutions of one model to countries belonging to a different model.     

A review of radon measurement studies in Pakistan.

Radon is being extensively measured all over the world due to its hazardous health effects as well as for different geological applications. In this regard, considerable studies have been conducted by different research groups in Pakistan. However, these studies are scattered and need to be combined/listed somewhere for future studies of radon in Pakistan. In this article, all the studies concerning radon measurements have been reviewed. The main emphasis is on different methods used in the measurement of radon. A minimum value of 5 Bq m(-3) has been reported for a centrally air conditioned room and a maximum value of 782 +/- 125 Bq m(-3) has been observed in coal mines of Khushab, Punjab.     

Indoor radon exposure and lung cancer risk: a review of case-control studies

BACKGROUND: Radon is a radioactive gas that tends to accumulate in indoor environment. A causal relationship between lung cancer and radon exposure has been demonstrated in epidemiologic studies of miners. The objective of this paper is to present the results of case-control studies of lung cancer risk associated with indoor radon exposure. METHODS: Case-control studies published since 1990 are included in this review. This type of protocol is particularly well suited for studying the relationship between indoor radon exposure and lung cancer risk, taking into account possible confounding factors such as tobacco smoking. The characteristics and results of these studies are summarized. The limitations associated with each of these studies are also discussed. RESULTS: The results of available studies are relatively concordant and suggest a positive association between lung cancer risk and indoor radon exposure with an estimated excess relative risk of about 6 to 9% per 100Bq/m3 increase in the observed time-weighted average radon concentration. The order of magnitude of this estimation agrees with extrapolations from miners but some studies may suffer from inadequate statistical power. CONCLUSION: At present, efforts are underway to pool together the data from the existing studies of indoor radon. This pooling analysis with thousands of cases and controls will provide a more precise estimate of the lung cancer risk from indoor radon exposure and explore the effect of modifying factors, such as smoking.     

A case-control study of bladder cancer in the United States rubber and tyre industry.

A case-control study of bladder cancer was conducted in five United States rubber and tyre companies to determine if there were high-risk jobs and work areas within the industry. The study included 220 male cases of bladder cancer, of whom 107 were identified from hospital record reviews and 113 from death certificates. Each case was matched individually with two industry controls by sex, race, year of birth, and company. One control was matched additionally by year of hire and duration of employment. Comparisons of cases and controls not matched by year of hire and age of hire showed no differences for those variables, which suggests that age and calendar period of first exposure to the industry were not risk determinants. When the work histories of both cases and controls were contrasted it was found that cases were more likely than controls to have worked in milling (odds ratio (OR) = 1.91) and calender operation (OR = 2.21) jobs. The relative risk estimates for milling and calender operation both exhibited linear trends of increase with duration of exposure. Milling and calender operation jobs entail potential exposures to volatilised reaction products from heated rubber stock. A better understanding of aetiological associations with job type will require more detailed characterisation of the work environment with regard to the sources and levels of aromatic amines and other suspected bladder carcinogens.     

Arsenic methylation and bladder cancer risk in case-control studies in Argentina and the United States

OBJECTIVE: We sought to assess whether the metabolism of arsenic impacts a person's susceptibility to bladder cancer. METHODS: Urinary methylation products were measured in subjects from Argentina (114 cases and 114 controls) and the United States (23 cases and 49 controls). RESULTS: In Argentina, the adjusted odds ratio (OR) for subjects with a high proportion of ingested arsenic excreted as monomethylarsonate (%MMA) was 2.17 (95% confidence interval [CI] = 1.02-4.63) in smokers and 0.48 (95% CI = 0.17-1.33) in nonsmokers. In the United States, the adjusted ORs for high %MMA in subjects with arsenic intakes less than and greater than 100 microg/d were 1.20 (95% CI = 0.27-5.38) and 2.70 (95% CI = 0.39-18.6). CONCLUSIONS: Overall, these results are consistent with data from Taiwan suggesting that some individuals who excrete a higher proportion of ingested arsenic as MMA are more susceptible to arsenic-related cancer.     

Oral contraceptives and colorectal tumors. A review of epidemiologic studies

Over the last two decades, the mortality rates of colorectal cancer in many developed countries have declined in women but not in men. One of the explanations of this difference between the genders may be the favorable influence of the spread of exogenous female hormone use (ie, oral contraceptives [OC] and hormone replacement therapy). Reduced risk in ever-users of OC was found in three of four cohort studies available on this topic, and was significant in the one based on colorectal cancer mortality. The fourth one showed no difference. Of 11 case-control studies (or groups of studies), none showed significantly elevated risk. Five reported lowered colorectal cancer risk among ever-users, with a significant inverse association in the largest investigation available. Recent OC use, more than long-duration use, seemed to be related to some risk reduction. One cohort study and three case-control investigations suggested that OC use was not related to the risk of colorectal adenomatous polyps. Thus, at present, it seems that OC use does not increase and may even have a favorable effect on either incidence or mortality of colorectal cancer.     

The incidence and epidemiologic characteristics of neuroblastoma in the United States

The incidence of neuroblastoma in the United States is described in relation to age, sex, race, and anatomic site, as well as population-derived indicators of socioeconomic levels, degree of urbanization, and farming activity. Incidence data were obtained for the years 1973-1978 from the Surveillance, Epidemiology and End Results Program of the National Cancer Institute. Based upon 265 cases, the overall incidence of neuroblastoma was 2.26 per million person-years. Approximately 60% of the cases were diagnosed under age two years, 75% under age five years and 84% under age 10 years. The incidence among males was 1.3 times that among females, but the male predominance was observed only among persons diagnosed under age five years. Although no difference in overall incidence was observed by race, the rate among whites was 1.6 times that among blacks and 1.5 times that among other nonwhites under age five years. Approximately 50% of all cases were diagnosed with tumors arising from the adrenals or soft tissues. No clear pattern of area-to-area variation in incidence was identified. Neuroblastoma incidence was inversely related to socioeconomic level as measured by per capita income (p = 0.05), as well as the proportion of county land devoted to farming (p = 0.034). No association was observed in relation to urbanization or population density.     

Accuracy of commercially available residential histories for epidemiologic studies

A key problem facing epidemiologists who wish to account for residential mobility in their analyses is the cost and difficulty of obtaining residential histories. Commercial residential history data of acceptable accuracy, cost, and coverage would be of great value. The present research evaluated the accuracy of residential histories from LexisNexis, Inc. The authors chose LexisNexis because the Michigan Cancer Registry has considered using their data, they have excellent procedures for privacy protection, and they make available residential histories at 25 cents per person. Only first and last name and address at last-known residence are required to access the residential history. The authors compared lifetime residential histories collected through the use of written surveys in a case-control study of bladder cancer in Michigan to the 3 residential addresses routinely available in the address history from LexisNexis. The LexisNexis address matches, as a whole, accounted for 71.5% of participants' lifetime addresses. These results provided a level of accuracy that indicates routine use of residential histories from commercial vendors is feasible. More detailed residential histories are available at a higher cost but were not analyzed in this study. Although higher accuracy is desirable, LexisNexis data are a vast improvement over the assumption of immobile individuals currently used in many spatial and spatiotemporal studies.     

Potential for bias in epidemiologic studies that rely on glass-based retrospective assessment of radon.

Retrospective assessment of exposure to radon remains the greatest challenge in epidemiologic efforts to assess lung cancer risk associated with residential exposure. An innovative technique based on measurement of alpha-emitting, long-lived daughters embedded by recoil into household glass may one day provide improved radon dosimetry. Particulate air pollution is known, however, to retard the plate-out of radon daughters. This would be expected to result in a differential effect on dosimetry, where the calibration curve relating the actual historical radon exposure to the remaining alpha-activity in the glass would be different in historically smoky and nonsmoky environments. The resulting "measurement confounding" can distort inferences about the effect of radon and can also produce spurious evidence for synergism between radon exposure and cigarette smoking.     

Models for retrospective quantification of indoor radon exposure in case-control studies

In epidemiologic studies on lung cancer risk due to indoor radon the quantification of individual radon exposure over a long time period is one of the main issues. Therefore, radon measurements in one or more dwellings, which in total have been inhabited by the participants for a sufficient time-period, are necessary as well as consideration of changes of building characteristics and ventilation habits, which influence radon concentration. Given data on 1-y alpha-track measurements and personal information from 6,000 participants of case-control studies in West and East Germany, an improved method is developed to assess individual radon exposure histories. Times spent in different rooms of the dwelling, which are known from a personal questionnaire, are taken into account. The time spent outside the house (average fraction 45%) varies substantially among the participants. Therefore, assuming a substantially lower radon exposure outside the dwelling, the residence time constitutes an important aspect of total radon exposure. By means of an analysis of variance, important determinants of indoor radon are identified, namely constant conditions such as type of house (one family house or multiple dwelling), type of construction (half-timbered, massive construction, lightweight construction), year of construction, floor and type of basement, and changeable conditions such as heating system, window insulation, and airing habits. A correction of measurements in former dwellings by factors derived from the analysis is applied if current living conditions differ from those of the participants at the time when they were living in the particular dwellings. In rare cases the adjustment for changes leads to a correction of the measurements with a factor of about 1.4, but a reduction of 5% on average only. Exposure assessment can be improved by considering time at home and changes of building and ventilation conditions that affect radon concentration. The major concern that changes in ventilation habits and building conditions lead to substantial errors in exposure (and therefore risk) assessment cannot be confirmed in the data analyzed.     

Exposure to residential radon and lung cancer in Spain: a population-based case-control study

Although high radon concentrations have been linked to increased risk of lung cancer by both experimental studies and investigations of underground miners, epidemiologic studies of residential radon exposure display inconsistencies. The authors therefore decided to conduct a population-based case-control study in northwest Spain to determine the risk of lung cancer associated with exposure to residential radon. The study covered a total of 163 subjects with incident lung cancer and a population sample of 241 cancer-free subjects since 1992-1994. Odds ratios for radon were estimated using logistic regression adjusted for sex, age, lifetime tobacco use, family history, and habitat. The adjusted odds ratios for the second, third, and fourth quartiles of radon (breakpoints: 37.0, 55.2, and 148.0 Bq/m(3)) were 2.73 (95% confidence interval (CI): 1.12, 5.48), 2.48 (95% CI: 1.29, 6.79), and 2.96 (95% CI: 1.29, 6.79), respectively. An additive synergic effect between radon and tobacco was found. The results from this study suggest that, even at concentrations far below official guideline levels, radon may lead to a 2.5-fold rise in the risk of lung cancer. Furthermore, the synergy found between smoking and radon may prove useful when it comes to drafting public health recommendations.     

A critical review of epidemiologic studies on black-foot disease

An endemic disease in Taiwan named "Black-foot Disease", which has been researched since 1958 and about which many papers have been published, was considered caused by arsenic poisoning from artesian well water. In the beginning some information related to the disease before 1958 is introduced and then, reviews of the six papers titled "Epidemiologic Studies" on "Black-foot Disease" are made without referring to any findings from other papers. The data related to the incidence and severity of the disease from the papers are reevaluated, paying special attention to the fact that the incidence of the disease increased after the installation of pipe system water-supply to replace the artesian wells. With the above-mentioned result the theory which considers arsenic poisoning as the cause of the disease, is disproved.     

A review of data on the health sector of the United States.

This report presents data on the state of U.S. health care in mid-2000. It provides information on the number of uninsured and underinsured (with special attention to health coverage among Hispanics and drug coverage among seniors); the increasing costs of health care; inequalities in the socioeconomic, health, and medical spheres; and the role of corporate money in health care. Recent data are presented on the pharmaceutical industry (with special notes on drug industry lobbying, drug safety, the use of publicly funded research to boost industry profits, and drug marketing to physicians) and the hospital and nursing home industries (including Medicare HMOs). The author also summarizes the health proposals of the presidential candidates, recent health care legislation, and some health system changes in Canada.