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Biomedical subjects

S Selvin

Publications and source records attributed to S Selvin.

At least 91 records · Page 5Linked to original sources
PubMed1979

Racial classifications based on blood group protein systems.

Two methods employing frequencies of blood group phenotypes are assessed as methods of accurately classifying individuals into racial categories. The data used consist of eleven blood group protein systems from 5043 males distributed into four ethnic categories (white, black, Chicano/Amerindian, and Asian). Both methods work equally well and yield a rate of misclassification of about 22%. Also included is a discussion of two probabilistic calculations relevant to employing blood group protein systems in the context of an identification tool.

Asian People↗
PubMed1978

Cohort mortality for prostatic cancer among United States nonwhites.

In recent decades, age-adjusted mortality rates from prostatic cancer have risen precipitously among blacks, remaining unchanged among whites. It is now the most common cancer among United States black males. When nonwhite mortality rates were examined by age and birth cohort, it was found that peak rates occurred at every age in the cohort of 1896 to 1900, and declined thereafter. This presages an arrest and reversal of the time trend in summary mortality rates as more recent nonwhite cohorts reach the ages of maximum risk.

Age Factors↗
PubMed1978

Prostatic cancer: mortality and incidence rates by race and social class.

Among the most striking epidemiologic characteristics of prostatic cancer in the United States is the sizeable excess in rates for the disease among blacks as compared with whites. This study attempted to determine whether the higher black rates might be explained by controlling for social class, using mortality data from Alameda County for the pericensal period 1968--1972 (n = 400), and the population-based series of cases for Alameda County included in the Third National Cancer Survey, 1969--1971 (n = 750). Reviewed first are previous studies addressed to the relationship of prostatic cancer and socioeconomic status (SES), most of which have been confined to whites. In the present study, each death or case was assigned to a socioeconomic class based on census tract of residence and rates by race and social class determined. Comparison of age-specific mortality and incidence rates by SES reveals no gradient for prostatic cancer in either whites or blacks.

Black or African American↗
PubMed1978

Frequency distribution and discrimination probability of twelve protein genetic variants in human blood as functions of race, sex, and age.

Fresh blood samples were obtained from 6004 whites, 1025 blacks, 1596 Chicano/Amerindians, and 3053 Asians of California and Hawaii. The samples were typed for ABO and Rh groups and were analyzed electrophoretically for ten genetically determined protein variant systems. The effects of race, age, and sex on phenotypic frequencies within each of the twelve genetic systems were investigated. Large frequency differences were found between races but not between different age and sex subgroups within races. It was also demonstrated that the twelve genetic systems behaved statistically independently. Discrimination probabilities were computed for each of the four ethnic groups. These serve as a measure of the effectiveness of the twelve genetic systems examined in individualizing blood samples. The method is discussed for computing the probability that a randomly chosen individual of a given ethnic group possesses the same blood phenotypes as found in a predetermined sample of blood. The results presented here should prove useful in the investigation of civil and criminal cases involving blood samples.

ABO Blood-Group System↗
PubMed1977

Efficiency of genetic systems for diagnosis of twin zygosity.

A definition of efficiency is presented to aid a researcher in the choice of the genetic systems for the diagnosis of twin zygosity. An expression is given that produces a numeric value that indicates which systems do the most effective job of discriminating DZ twins from a sample of twin pairs. This definition of efficiency is illustrated with eight blood groups commonly used in twin zygosity diagnosis.

Alleles↗
PubMed1977

Brief communication: Possible increased risk of lung cancer among beauticians.

Death certificates of residents of Alameda County, California (1958-1962) with any mention of cancer were examined to determine the risk of cancer among beauticians. Twenty-four female beauticians were found among 3,460 adult females who died with cancer; four female beauticians were found in a sample of 1,000 females who died from causes other than cancer. The case and control certificates were matched for age and race. The resulting odds ratio (i.e., approximate relative risk of a cancer death) was slightly elevated (1.73) but was not statistically significant. Although a possible increase in the risk of cancer was found for several organ sites, the increase in risk for lung cancer was most striking. Analysis of pairs of death certificates, in which female controls dying of causes other than cancer were matched to female lung cancer cases for age, race, and date of death, yielded an odds ratio of 6.0. This finding suggested that the risk of lung cancer may be substantially increased among female beauticians.

Adolescent↗
PubMed1977

Correlations of incidence rates for selected cancers in the nine areas of the Third National Cancer Survey.

Incidence date from the Third National Cancer Survey were used to study geographic variation in the occurrence of nine common cancers of nonsexual sites and five sexual sites. It was hypothesized that cancers which varied together across the nine survey communities might have common etiologic factors. The variation was measured by a series of rank and product-moment correlation coefficients in order to summarize the association between pairs of cancers in white males and in white females. The most notable findings were the high correlations between the incidence rates for the three gastrointestinal sites (stomach, colon, and rectum) and bladder cancer in both men and women and the high correlation between three female sexual sites (breast, corpus, and ovary). These two clusters are also correlated with one another. A number of other substantial correlations between pairs of cancers were observed and discussed. These associations suggest possible common etiologic agents, despite the fact that the individual secular trends for some of these cancers differ.

Breast Neoplasms↗
PubMed1977

Expired air carbon monoxide and serum thiocyanate as objective measures of cigarette exposure.

Expired air carbon monoxide (CO) and serum thiocyanate (SCN) were used to asses exposure to cigarettes in 139 middle-aged men. Subjects who reported smoking cigarettes generally had CO levels exceeding 8ppm and SCN levels exceeding 100umol/L; non-smokers had lower levels. For both tests the mean concentration among men smoking more than one pack daily was three times that of non-smokers. The is a high correlation between the two tests (r=.571 for smokers), an association that was largely independent of the smaller correlations between either test and reported smoking frequency (r=.476 for CO; r=.479 for SCN). The ability to distinguish between individuals who reported "typical" smoking habits and non-smokers was best when the CO and SCN analyses were used together to take advantage of their separate sources of variance; it was 99 per cent when the two tests were mutually concordant (91 per cent of cases). The CO and SCN measurements allowed 16 individuals who reported light smoking habits to be categorized into high and low presumptive tobacco exposure groups. The two tests are inexpensive and suitable for use in epidemiologic and health care delivery programs.

Adult↗
PubMed1977

Three statistical models for estimating length of stay.

The probability density functions implied by three methods of collecting data on the length of stay in an institution are derived. The expected values associated with these density functions are used to calculate unbiased estimates of the expected length of stay. Two of the methods require an assumption about the form of the underlying distribution of length of stay; the third method does not. The three methods are illustrated with hypothetical data exhibiting the Poisson distribution, and the third (distribution-independent) method is used to estimate the length of stay in a skilled nursing facility and in an intermediate care facility for patients enrolled in California's MediCal program.

California↗
PubMed1975

The association of economic status with the occurrence of lung cancer.

Lung cancer in men was shown to be inversely associated with economic class by analysis of 1959-61 mortality rates from Buffalo, New York. Using five economis strata, white men below and above age 55 in the poorest group had rates 2.6 and 3.8 times higher than those in the richest. For women, the trend was not significant. The question that was investigated was whether, for males, an economic-class trend for smoking existed which paralleled that for lung cancer. Individuals from a Buffalo sample survey were classified according to cigarette smoking habits. Age was found highly associated with both smoking and economic class. In data from white males stratified for age, no significant association was observed between smoking and econimic class. In women, the upper economic groups smoked more, particularly those above age 55. Thus, a strong inverse economic class gradient for lung cancer in men, observed by other investigators among women, cannot be explained by class-related cigarette smoking patterns alone. The possible interaction of cigarette-smoking with other potential etiologic factors that may be associated with economic class is discussed.

Adult↗
PubMed1975

Testing the Mendelian segregation ratio under incomplete ascertainment.

The properties of a test, suggested by HALDANE [1938], for a Mendelian segregation ratio of 0.25 when ascertainment is incomplete are investigated. The error rates associated with this procedure show the weakness of this specific test. An alternative test based on a chi2 statistic is illustrated with the data on human albinism originally analyzed by HALDANE [1938].

Albinism↗