Exposure Reconstruction for the TCDD-Exposed NIOSH Cohort Using a Concentration- and Age-Dependent Model of Elimination

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.     

Physician-nurse migration to the United States: regional and health status origins in relation to legislation and policy

This article examines the origins of physicians and nurses who were admitted as permanent immigrants to the US from 1962-1979. Data are mainly from the Immigration and Naturalization Service. Countries used in the developmental analysis are only those whose population was estimated at 1 million or more as of mid-1979, encompassing 99% of the physicians and 97% of the nurses. Life expectancy at birth is the criterion used to differentiate origin countries by developmental dimension of health status. During the study period, health workers constituted about 30% of immigrants admitted to the US; of these, nurses and physicians constituted 72-82% throughout the study period. The period 1962-1979 has 4 distinct phases, marked by important legislative and/or policy changes; 1) 1962-1965, when the McCarran-Walter Act prevailed; 2) ending in 1968, the 2nd phase covers the transition mandated under the 1965 Immigration Act, which encouraged physician immigration; 3) the 3rd phase, 1969-1976, covers the transition to the 1976 Immigration and Nationality Act amendments; and 4) the 4th stage is 1977-1979. Results show that 1) under the McCarran-Walter Act, North America became the dominant physician source; 2) from 1966-1968, Asia attained dominance as the physician source and became even more predominant after 1968; 3) North America produced relatively few physicians in the early 1970s; 4) Europe produced substantially fewer physicians in the 1970s than in the 1960s; 5) South America, Africa, and Oceania were the lowest contributors of physicians; 6) during the McCarran-Walter years, North America and Europe produced almost 90% of nurses admitted into the US; 7) the 1965 Immigration Act and its aftermath resulted in Asia becoming the dominant source of nurses; 8) prior to the 1965 Immigration Act, Canada generated 20% of the aggregate number of physicians; 9) the Philippines surpassed Canada during the transition and India led after the transition; and 10) Canada supplied 30% of the nurses up through the transition, with the Philippines in the lead 1969-1979. Low health status countries were a relatively minor nurse source. Health status at the origin was a far less significant determinant of physician immigration than that of nurses. English language high and low health status country groups produced substantially more physician and nurse immigrants that their corresponding non-English language counterparts. The US attracted more physicians and nurses from less developed countries than more developed countries after 1968.     

The prevalence rates of pathological gambling: A look at methods

Planning the gambling environment requires protection of the public's health, safety and welfare. Whereas most public gaming provisions and statutes address the public's fears of organized crime as well as some welfare needs, rarely do they safeguard the public's health regarding the spread of the mental disease known as pathological gambling. Measurement of the prevalence and incidence of this disease would enable policy planners to evaluate both the state's responsibility for an epidemic and the adequacy of publicly funded treatment programs. The purpose of this paper is to examine the methods which underlie three different estimates of the prevalence rate of pathological gambling and to critique them in the light of sound epidemiological procedure. In 1975, the Institute for Social Research (ISR) of the University of Michigan conducted a national survey and a survey of the state of Nevada on behalf of the U.S. Commission on a National Policy Toward Gambling. Using discriminant function analysis coupled with subjective inspection of cases in the at-risk pool, the researchers estimated rates of probable and potential pathological gamblers. In 1984 and 1985, this author surveyed residents in the Delaware Valley and the state of Ohio using the cumulative clinical signs method which also posited rates of probable and potential pathological gamblers. In 1986, researchers at the Office of Mental Health for the State of New York employed a formal screening device to survey residents and proposed a rate of probable pathological gamblers and a rate of problem — although not pathological — gamblers. All three approaches produced different estimates. The utility of prevalence and incidence rate research in this field is threatened by a lack of consensus about the proper epidemiological procedure to be employed in arriving at these estimates. There is also confusion about the distinction between a probable and a potential pathological gambler. The planning purpose, method, validity and reliability of prevalence rate research about pathological gambling are addressed in this paper.     

Book reviews

Nathan Glazer Ethnic Dilemmas Harvard, Harvard University Press. 1985

Giddens, Anthony The Constitution of Society, Berkeley, University of California, 1985, pp.XXXVII, 402. Notes, glossary, diagrams, bibliographic notes and index.

Jeremy Rifkin Declaration of a Heretic. Boston. London, Melbourne and Henley, Routledge and Kegan Paul, 1985, pp.X,140.

Ted Benton The Rise and Fall of Structural Marxism: Althusser and his Influence, New York, St.Martin's Press, 1984, pp. VII,259.

Raymond L. Garthoff Détente and Confrontation Washington, The Brookings Institution, 1985, pp.XVI,1126.

Joseph J. Collins The Soviet Invasion of Afghanistan. A Study in the Use of Force in Soviet Foreign Policy, Massachusetts/Toronto, D.C. Heath and Company/Lexington, 1986, pp. XV, 195.

Jan Shipps Mormonism: The Story of a New Religious Tradition, Chicago, University of Illinois Press, 1985, pp.211.

Robert Jay Lifton Home from the War: Vietnam Veterans: Neither Victims nor Executioners, New York, Basic Books, 1985, pp.478     

The influence of income on family fertility in the light of the results of empirical studies

Based on data from the 1973-83 Polish Family Budget Survey, this study examines the influence of income as a source of maintenance and income as a determinant of childbearing on family parity. It is assumed that income influences parity as a source of maintenance and as an influence on lifestyle or reproductive behavior. As a source of maintenance, the influence will be positive. As a life-style factor, it could be positive or negative. The hypotheses are 1) that positive influences are characteristics of older couples with a lower educational level and living in villages and small towns and income is a source of maintenance, and 2) a negative influence on parity reflects younger couples with higher educational levels from larger cities and income is a life-style factor. Some examples of how the theory of income influences total fertility are given in addition to a further elaboration of the theory. Other concepts introduced, as related to childbearing, are the value of goods and services with unchanged preferences and an increase in income, with preferences changing with income increases, with income preferences for nonprocreational and for procreational needs, and income as a factor influencing procreational needs and behavior. Correlation analysis is conducted for 33 subpopulations based on duration of marriage, educational level of the household, and size of residence. The results indicate that, in years 1973, 1975, and 1978 when income and parity are significant, the sign is positive. In 1980, there was a decrease in the number of subpopulations with a significant relationship, and in 3 subpopulations the results were negative. The 13 positive subpopulations were similar to those in the 1970s. In 1983, income explained an even smaller amount of parity. The subpopulations with a postive relationship usually have longer marriage durations, which suggest income as a source of maintenance. Negative results were among subpopulations with shorter marriage durations, which suggests life-style factor effects of income.     

Estimating the National High School Dropout Rate

Recent interest has focused on the high school dropout rate as one indicator of the national education picture. Empirical estimates of this "rate" vary considerably, because these estimates are poorly defined. This article reviews some of the current measures and presents a new measure of the high school dropout rate--the proportion of high school students who drop out in a defined period of time (1 year). The estimates show that the national yearly high school dropout rate was about the same in 1985 as it was in 1968. Improvement has occurred, however, since 1968 for specific racial groups as well as for some grade levels.     

Mortality among three Puerto Rican populations: residents of Puerto Rico and migrants in New York City and in the balance of the United States, 1979-81

"This study attempts to explain similarities and differences in the mortality experience of three population groups: Puerto Ricans on the island commonwealth, Puerto Rican born persons in New York City and Puerto Rican born persons in the rest of mainland United States. Mortality is much higher among Puerto Ricans in New York City than among those residing elsewhere. Much of the difference is due to excess mortality caused by cirrhosis of the liver and homicide. Puerto Rican born persons living on the mainland but outside New York City generally have low mortality, even when compared with U.S. whites."     

Gambling and the Law®: Endless fields of dreams

This article examines the current trends of proliferation of commercial gaming, especially in the United States, in the context of the third wave of legalization of gambling that has been experienced since the founding of the nation. The author looks at the historic foundations of the spread of casino-style gambling, and notes the types of casino gaming that have led the way in the current expansion. He also points out why it is reasonable to expect that this wave too may come crashing down, as general acceptance of wide-spread casino gaming in America may indeed be short-lived.Gambling and the Law^® is a registered trademark of I. Nelson Rose.