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For the first 30 years after repatriation, former American prisoners of war (POWs) of World War II and the Korean Conflict had lower death rates for heart disease and stroke than non-POW veteran controls and the U.S. population, but subsequent morbidity data suggested that this survival advantage may have disappeared. We used U.S. federal records to obtain death data through 1996 and used proportional hazards analysis to compare the mortality experience of POWs and controls. POWs aged 75 years and older showed a significantly higher risk of heart disease deaths than controls (hazard ratio = 1.25; 95% confidence interval, 1.01-1.56), and their stroke mortality was also increased, although not significantly (hazard ratio = 1.13; 95% confidence interval, 0.66-1.91). These results suggest that circulatory disease sequelae of serious, acute malnutrition and the stresses associated with imprisonment may not appear until after many decades.

At least two twin registries in the United States have been or are being assembled using the similarity of Social Security Numbers in computerized records to help identify possible twin pairs. While the success of such enterprises depends directly on a high probability of twinness given Social Security Numbers, there are theoretical and practical reasons to study the probability of Social Security Number similarity given twinness. For example, the number of twin pairs with similar Social Security Numbers obviously determines the maximum number of twin pairs that can be discovered by similarity algorithms. To study this issue, we examined the similarity of known Social Security Numbers in twin pairs from the Virginia Twin Registry by age, sex, race, and zygosity of the pair. We found that similarity between the Social Security Numbers of twin pairs varies markedly by age, and MZ twin pairs have significantly more similar Social Security Numbers than DZ pairs at all ages. Among older twins, there are also significant differences by sex and race. For younger twins, algorithms that identify putative twin pairs on the basis of the similarity of their Social Security Numbers hold the promise of being able to identify a large proportion of all true twin pairs. Such algorithms will be substantially less successful, however, in identifying a large proportion of older twin pairs.

Increased risk of prostate cancer among men with a family history of the disease has been observed in several epidemiological studies, and family studies have identified hereditary prostate cancer characterized by early onset and autosomal dominant inheritance.In this study, we examine prostate cancer heritability among twins in the NAS-NRC Twin Registry, with cases ascertained from a number of sources: recent telephone interviews, Medicare and Department of Veterans Affairs hospitalizations, previous mail questionnaires, and death certificates. A total of 1,009 prostate cancer cases were identified among the cohort of 31,848 veteran twins born in the years 1917-1927.Probandwise concordance for prostate cancer was substantially higher among monozygous twin pairs, 27.1%, than among dizygous twin pairs, 7.1% (P0.001).These data suggest that genetic influences account for approximately 57%, and environmental influences for 43%, of the variability in twin liability for prostate cancer.

Myocardial infarction and stroke are both predominantly manifestations of atherosclerosis, yet stroke is commonly ignored in prognostic studies and therapeutic trials of ischemic heart disease. Our objective was to assess, in a community setting, the relative importance of stroke among patients at high risk for myocardial infarction.We analyzed 1985 survey data from the National Academy of Science Twin Registry of white male veterans. To minimize confounding by genetic and environmental factors, we restricted our analysis to the rates of stroke and myocardial infarction among monozygotic twins counted as individuals or as twin pairs.Among 2764 monozygotic twins aged 58 to 68 years, the overall rate of myocardial infarction was 10% and stroke 3.1%. Among 2632 individual monozygotic twins (95%) with complete responses, the rate of stroke among men with a history of myocardial infarction was 7.5% (17/228) compared with 2.4% (58/2404) among those without myocardial infarction (odds ratio = 3.3, chi square 2 = 19.1, P.001). A strong association between stroke and myocardial infarction was also found when the data were analyzed for twin pairs (chi square 2 = 135, P.0005).Our results suggest that stroke, in addition to myocardial infarction, should be considered as an outcome in clinical investigations of ischemic heart disease.

Veterans now make up nearly two-thirds of U.S. males aged 65 and older, and thus medical research in the male geriatric population is largely concerned with veterans, whose mortality experience assumes greater importance as they age. Department of Veterans Affairs (VA) records provide an effective and efficient means of gathering information on mortality of veterans, but are useful only if they provide relatively complete ascertainment. We investigated the completeness of VA death reporting (via the Beneficiary Identification and Records Locator Subsystem [BIRLS]) in a large cohort of nearly 32,000 World War II veteran twins followed from 1946 through 1990, comparing VA and Social Security Administration (SSA) mortality ascertainment. The small number of additional deaths found using SSA records--roughly 3% of total deaths--provides evidence that VA death reporting was nearly complete. A further capture-recapture analysis, assuming independence of BIRLS and SSA mortality ascertainment, indicated that BIRLS ascertainment was 95.4% complete.

Given the current explosion of knowledge of the genetics and molecular biology of cancer, the possibility of widespread testing for inherited predisposition to cancer has been raised. The main objective of this study was to assess the effect of inherited predisposition on cancer mortality among the National Academy of Sciences-National Research Council Twin Registry. The twins were white male United States veterans of World War II, who were born during the period 1917-1927. The follow-up period was from 1946 to 1990, and some cause of death was determined with the use of death certificates. We compared concordance for death from cancer among 5690 monozygotic twin pairs to that among 7248 dizygotic pairs. A possible effect of inherited predisposition to death from cancer was considered present if concordance for cancer mortality among monozygotic twin pairs was greater than it was among dizygotic twin pairs. Among monozygotic and dizygotic twins, a total of 1918 cancer deaths was observed. Concordance for death from cancer at all sites among monozygotic twins was higher than it was among dizygotic twins (overall rate ratio, 1.4; 95% confidence interval, 1.0-2.0). For each zygosity group, two or fewer pairs were observed to be concordant for death from cancer of a specific site, with the exception of lung cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Prior studies have suggested that the risk of testicular cancer among dizygotic twins may exceed that among monozygotic twins or the general population. Cryptorchidism is associated with testicular cancer and twinship, and therefore might potentially explain the findings of the prior studies. In 1993-1994, when they were 66 to 77 years of age, 14,326 twin individuals in the National Academy of Sciencies-National Research Council Twin Registry were interviewed by telephone. A history of testicular cancer was reported by 5 (0.08%) of 5951 monozygotic twins and 11 (0.16%) of 6992 dizygotic twins. Follow-up interviews concerning testicular cancer risk factors and treatment were able to be administered to 4 of the monozygotic and 9 of the dizygotic twins reporting testicular cancer. A history of cryptorchidism was reported in the follow-up interview by only one dizygotic twin. Our data agree with the results of prior studies reporting a more frequent occurrence of testicular cancer among dizygotic than monozygotic twins. Although somewhat limited by small numbers, our study also suggests that the findings of increased testicular cancer in dizygotic twins are not explained simply by increased occurrence of cryptorchidism in twins.

Previously, we studied the effect of population ancestry on the risk of multiple sclerosis (MS) in US veterans of World War II, comparing by state 1980 US census ancestry data with MS case/control ratios. Here, the joint effects of population ancestry and surname-derived ethnicity on MS risk are examined in the same series. Census data are used again to characterize the population ancestry of the state from which each subject entered active duty (EAD)--that is, the proportions of the populace reporting various ancestries--and subjects were also individually categorized into a single ethnic group, without knowledge of case/control status, based on surname. In this study population, categorized ethnicity was strongly correlated with population ancestry, as expected. Although univariate analyses showed statistically significant associations between MS risk and several surname-derived ethnicities and ethnic groups, when residence at EAD was accounted for as well, there was almost no ethnic variation in MS risk. A logistic regression analysis further showed that variations in MS risk are associated most strongly with latitude and population ancestry group; in particular, subjects who entered military service from states with higher proportions of Swedish or French ancestry had higher risks of MS. After adjustment for characteristics of place, the only significant individual ethnicity factor found was Southern European ethnicity. In general, we conclude that an individual's ethnicity seems to be of less relative importance in determining MS risk than is the population ancestry of the state of EAD. These findings underscore the fact that MS is a disease of place, with 'place' including not only attributes of the locale (e.g., latitude), but also of its populace (e.g., ancestry).

The role of genetic and shared environmental influences in the association of alcohol with mortality was studied by using the National Academy of Sciences-National Research Council World War II-veteran male twin registry. An epidemiologic questionnaire administered from 1967 through 1969 permitted identification of twin pairs discordant for alcohol consumption. The subsequent 24 years of mortality follow-up yielded data on time and cause of death. Analyzing the first or only death in drinking-discordant pairs, we observed 27 deaths in abstainer twins and 14 deaths in their light- to moderate-drinker cotwins (relative risk [RR] = 1.93). Excess mortality in twin abstainers was also indicated for deaths from cardiovascular diseases (RR = 2.0) and other causes of death excluding cancers (RR = 3.2). The protective effect, however, of light to moderate drinking did not persist in twins who were smokers at baseline.

A retrospective longitudinal analysis of fat distribution and cause-specific mortality was performed on data from 105,062 men discharged from the United States Army in 1946-47. Baseline height, weight, waist and hip girth, and 23-year follow-up mortality data were available for 84,910 white men. Proportional hazard survival analysis was performed by 5-year age group for waist/hip ratio (WHR) and for body mass index (BMI) in prediction of time to death from ischaemic heart disease (IHD) and stroke. Relative risk of IHD fatality per standard deviation (s.d.) of WHR ranged from 1.11 to 1.17, the higher values appearing in younger age groups. Relative risk due to BMI was not significant in the group aged 16-20 years at time of discharge from service, but ranged from 1.22 to 1.25 per s.d. among the 21-30 year olds. WHR was predictive of cerebrovascular disease mortality among 16-25 year olds, carrying a relative risk of 1.24 to 1.35 per s.d. BMI was not predictive of cerebrovascular disease mortality in any age group. Multivariate models indicated that WHR and BMI were related to subsequent IHD independently of each other in most age groups. WHR and BMI both contribute to risk of premature IHD mortality and WHR to risk of cerebrovascular disease mortality in an initially relatively healthy population of young men, although the effects are not equivalent in all age groups.

Age at onset of multiple sclerosis (MS) symptoms was ascertained for subsets of some 4,400 veterans of World War II who had been adjudged 'service-connected' for this condition. Average age at onset was 27.0 years for white men, 27.7 for white women, and 27.5 for black men. The unexpectedly older age for women is attributed to their older age at entry into service. When the coterminous United States was divided into three horizontal tiers of states, we found a strong effect of geography on age at onset. By state of residence at entry into active duty (EAD), white men had an average age at onset of 26.4 years in the northern tier, 27.3 years in the middle, and 28.8 years in the south. Trends were similar for white women and black men. Migrants, defined as those whose birth and EAD tiers differed, showed increasing ages at onset with southward moves. A statistical model used to discriminate between the influence of birth and EAD tiers on age at onset confirmed the significant effect of EAD alone. These data are compatible with the theses that the cause of MS is less common (or less efficient) in locations where the clinical disease is less common, and that its acquisition therefore occurs at an older age in those locales.

Mortality odds ratios (MORs) comparing veterans with Vietnam service who died in New York State to veterans of the Vietnam era with no Vietnam service were estimated (N = 1,496). The most elevated MORs and their confidence intervals were non-motor vehicular injuries of transport (MOR = 2.18, (1.19, 3.96)), other accidents and burns (MOR = 1.37, (0.95, 1.98)), and homicide (MOR = 1.59, (0.86, 2.94).

The results of a small experiment in address tracing have shown that subjects who were found by commercial tracing were less apt to have moved and were especially apt to have remained in the same state. The documented relation of migration and health status means that differential success in subject tracing can lead to subsequent study bias. Therefore, those who use commercial tracing of epidemiologic study subjects must carefully consider the possibility of a "missing migrant" effect, and that it may, in turn, produce a subsequent survey bias.

The prevalence of tonsillectomy and appendectomy was higher in 196 patients with rheumatoid arthritis (RA), prior to the onset of articular disease, than in their spouses and siblings. The estimated increased risk of developing RA with tonsillectomy was 1.5 and 3.5 times, with appendectomy 1.7 and 6.6 times, and with both surgical procedures 2.3 and 6.7 times, using patient-spouse and patient-sibling matched-pair data, respectively. However, only with patient-sibling data did the lower limits of the 95% confidence interval for the risk ratio exceed 1.0. Several hypotheses are offered to explain the possible association between these surgical procedures and RA.

Previous studies have documented a substantially lower mortality rate among US male veterans, a form of the "healthy worker" effect, but there have been no studies of morbidity selection effects among veterans. In this paper the evidence for mortality selection effects among US male veterans is reviewed, and data from two general health surveys are examined for evidence of a morbidity selection effect. Overall, there are no substantial differences in health characteristics between veterans and nonveterans, thus providing no evidence for a morbidity selection effect; the inclusion of military service-connected disabled veterans in this comparison, however, makes it somewhat problematic. Reconciliation of a clear mortality selection effect for veterans with the lack of evidence for a corresponding morbidity selection effect is attempted.

The survival experience of 46,000 Veterans Administration (VA) male cancer patients was analyzed and compared with the results of three other studies. In the VA data, no significant differences were found between white and black patient cancer survival rates except for bladder cancer; this observation differs from those in other studies. In the VA, all patients receive the same treatment with no distinctions whereas most U. S. hospitals place their patients into categories based on ability to pay. This factor probably accounts for the lack of racial differences in survival rates in the VA and the existence of racial or socioeconomic differences in survival rates in the other studies.