Long-term heart disease and stroke mortality among former American prisoners of war of World War II and the Korean Conflict: results of a 50-year follow-up.

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.

Breast cancer risk in male twins: joint analyses of four twin cohorts in Denmark, Finland, Sweden and the United States.

To test the hypothesis that in utero exposure to high levels of oestrogen increases the risk of male breast cancer, we followed 115 235 male twins for more than 3.5 million person-years at risk. We observed 11 cases of male breast cancer versus 16.16 expected based on national rates (standardized rate ratio 0.68, 95% confidence interval 0.34-1.22) and conclude that any adverse influence of in utero oestrogen exposure is likely to be small.

Cirrhosis mortality among former American prisoners of war of World War II and the Korean conflict: results of a 50-year follow-up.

In our earlier, 30-year follow-up of American prisoners of war (POWs) of World War II and the Korean conflict, we found evidence of increased cirrhosis mortality. Using federal records, we have now extended our follow-up to 50 years (42 years for Korean conflict veterans) and have used proportional hazards analysis to compare the mortality experience of POWs with that of controls. Compared with their controls, World War II POWs had a 32% higher risk of cirrhosis mortality (statistically significant), and mortality risk was higher in the first 30 years of follow-up and also among those aged 51 years and older. Korean POWs had roughly the same risk of cirrhosis mortality as their controls. Neither self-reported data on alcohol consumption nor supplemental morbidity data satisfactorily explained the differences in risk between POWs and controls, although there was evidence that POWs tended to have higher rates of hepatitis, helminthiasis, and nutritional deprivation.

Epidemiology of multiple sclerosis in US veterans. VIII. Long-term survival after onset of multiple sclerosis.

Survival to 1996 was analysed for nearly 2500 veterans of World War II who were rated as 'service-connected' for multiple sclerosis as of 1956 by the then Veterans Administration. Survival from onset was defined for all white women and black men, and a random sample of white men. Median survival times from onset were 43 years (white females), 30 years (black males) and 34 years (white males). Crude 50-year survival rates were 31.5% (white females), 21.5% (black males) and 16.6% (white males), but only the white females and white males were significantly different. A proportional hazard analysis was used to identify risk factors for mortality from multiple sclerosis onset year. Significant risk factors included male sex (risk ratio: 1.57), older age at onset (risk ratio: 1.05 per year) and high socioeconomic status (risk ratio: 1.05 per socioeconomic status category). There were no statistically significant differences in survival following multiple sclerosis onset by race or latitude of place of entry into military service, both significant risk factors associated with the development of multiple sclerosis. Standardized mortality ratios utilizing national US data (for 1956-96) showed a marked excess for all three race-sex groups of multiple sclerosis cases, with little difference among them, but with a decreasing excess over time. Relative survival rates, used to compare the survival of multiple sclerosis cases with that of other military veterans, did not differ significantly by sex-race group, nor by latitude of place of entry into military service, but did differ significantly by socioeconomic class. The lack of difference in male and female relative survival rates suggests that the significant difference in survival between male and female multiple sclerosis cases is, at least in part, a result of sex per se and not the disease.

A comparison of melanoma mortality among WWII veterans of the Pacific and European theaters.

PURPOSE: To determine whether cutaneous melanoma is associated with past military service in tropical locations, as a test of the 'critical period' sunlight exposure hypothesis. METHODS: Mortality data from a longitudinal follow-up study of 5524 former prisoners of war (POW) and 3713 non-POW veteran controls, all white male veterans of World War II (WWII), were examined to determine whether death attributed to melanoma was associated with history of military service in Pacific or European theaters during WWII or with POW status. Deaths from colon cancer were used as a comparison outcome. RESULTS: During 50 years of follow-up, there were 18 deaths from melanoma and 83 deaths from colon cancer among the cohort. Melanoma mortality varied with theater of war and POW status, whereas colon cancer mortality was similar for all subgroups. Pacific War POWs were at the highest risk overall (odds ratio (OR), 3.35; 95% confidence interval (CI), 0.39-28.76), whereas veterans of the Pacific War had nearly the same risk of melanoma (OR, 1.04; 95% CI, 0.09-11.94) compared with veterans of the European War. European theater POWs had a higher risk than non-POW veterans (OR, 2.76; 95% CI, 0.31-24.81). None of these differences, however, were statistically significant. CONCLUSIONS: To the extent that POW status is associated with higher sun exposure, these data are consistent with the hypothesis that exposure to high levels of solar radiation in young adulthood is associated with a higher risk of melanoma mortality.

Trauma exposure, resilience, social support, and PTSD construct validity among former prisoners of war.

BACKGROUND: The aim of this study was to investigate predictors of persistent symptoms of posttraumatic stress disorder (PTSD) and to examine the construct validity of PTSD in a national sample of 270 World War II and Korean Conflict prisoners of war (POWs). METHOD: POWs were interviewed at two points in time (1965 and 1990). Predictors included PTSD symptomatology measured in 1965 by items from the Cornell Medical Index (CMI), severity of captivity trauma, resilience factors, and post-trauma social support. The criterion, symptomatology in the early 1990s, was evaluated with the PTSD module of the Structured Clinical Interview for DSM (SCID). RESULTS: The CMI provided only partial coverage of PTSD criteria and appeared to provide only a general index of distress. Clustering of SCID items in two-dimensional space via multidimensional scaling analysis offers some construct validation for the DSM's differentiation of PTSD symptoms into criterion groups, although there was not a perfect match. Trauma severity is best related to PTSD symptomatology experienced in 1990, mitigated in part by greater education level and age at the time of trauma exposure. Surprisingly, 1965 distress added only a modest amount to the prediction of current distress, while post-trauma social support added none. CONCLUSIONS: These findings support previous work showing the severe psychological sequelae of POW status 40-50 years after captivity, and indicate that trauma severity during captivity is the best predictor of current PTSD symptomatology. Results also add to our understanding of the conceptual differentiation of PTSD symptoms into separate and distinct symptom clusters.

Similarity of social security numbers among twins: data from the Virginia Twin Registry.

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.

Heredity and prostate cancer: a study of World War II veteran twins.

BACKGROUND: 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. METHODS: 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. RESULTS: Probandwise concordance for prostate cancer was substantially higher among monozygous twin pairs, 27.1%, than among dizygous twin pairs, 7.1% (P < 0.001). CONCLUSIONS: These data suggest that genetic influences account for approximately 57%, and environmental influences for 43%, of the variability in twin liability for prostate cancer.

Mortality of veteran participants in the CROSSROADS nuclear test.

Operation CROSSROADS, conducted at Bikini Atoll in 1946, was the first post World War II test of nuclear weapons. Mortality experience of 40,000 military veteran participants in CROSSROADS was compared to that of a similar cohort of nonparticipating veterans. All-cause mortality of the participants was slightly increased over nonparticipants by 5% (p < .001). Smaller increases in participant mortality for all malignancies (1.4%, p = 0.26) or leukemia (2.0%, p = 0.9) were not statistically significant. These results do not support a hypothesis that radiation had increased participant cancer mortality over that of nonparticipants.

Epidemiology of multiple sclerosis in US veterans: VII. Risk factors for MS.

In previous papers of this series, we explored the epidemiology of MS, examining the effects of race, sex, geography, latitude and climate, migration, age at onset, population ancestry, and individual ethnicity on the risk of MS, using an unusually large cohort of MS cases and pre-illness matched controls comprising US veterans of World War II (WWII) and the Korean Conflict (KC). In this paper, we examine primarily the effect of other factors on the risk of MS in this cohort and their relation to those previously studied. We found here that latitude tier of residence at entry into active duty (EAD), years of education, and socioeconomic class (coded from occupation) were similarly associated with MS risk among white men, black men, and white women. Higher levels of each factor showed increased MS risk. Multivariate analyses indicated that for white male WWII subjects an urban address, 9 or more years of education, uncorrected visual acuity less than 20/20 at EAD, a more northern latitude, and a higher proportion of the subject's EAD state population reporting Swedish ancestry each significantly increased the risk of MS. White male KC subjects showed roughly the same patterns, except that uncorrected visual acuity less than 20/20 was associated with lower MS risk (ancestry/ethnicity was not studied). For black male WWII and KC subjects combined, a similar analysis (omitting ancestry/ethnicity) showed that only latitude at EAD and 9 or more years of education were independently associated with a significantly higher MS risk, and for WWII plus KC white women (also without ancestry/ethnicity), only latitude was a significant risk factor in these multivariate analyses. The smaller number of subjects, especially in these last two groups, limited the power to detect statistically significant risks in these last analyses. Similarities to white men of WWII in univariate analyses for all other groups suggest that findings for the former would otherwise apply to the latter. Although the interpretations of these associations may be obscure, in addition to geography, age, sex, and race, per se, higher socioeconomic status is significantly associated with higher MS risk in black and white men and in white women in the United States.

Genetic predisposition to organ-specific endpoints of alcoholism.

Medical records of the 15,924 twin-pairs in the National Academy of Sciences-National Research Council (NAS-NRC) twin registry were collected for an additional 16 years through 1994 when the surviving twins were aged 67 to 77 years. Compared with earlier analyses (Hrubec, Z, and Omenn, G. S., Alcohol. Clin. Exp. Res., 5:207-215, 1981), when subjects were aged 51 to 61, there were 23% more diagnoses of alcoholism (34.4 per 1,000 prevalence), 32% more diagnoses of alcoholic psychosis (5.4 per 1,000), and 25% more twins with liver cirrhosis (17.7 per 1,000). Overall, 5.3% of the cohort had at least one of the diagnoses related to alcoholism. Probandwise concordance rates (%) were: alcoholism-26.7 monozygotic (MZ), 12.2 dizygotic (DZ) (p < 0.0001); alcoholic psychosis-17.3 MZ, 4.8 DZ (p < 0.05); and cirrhosis-16.9 MZ, 5.3 DZ (p < 0.001). Concordance for any diagnosis related to alcoholism was 30.2 MZ, 13.9 DZ (p < 0.0001). Maximum-likelihood modeling indicated that approximately 50% of the overall variance was due to additive genetic effects; in all diagnosis categories, a totally environmental model gave a significantly poorer fit to the data. Bivariate and trivariate genetic analyses indicated most of the genetic liability for the organ-specific endpoints of psychosis and cirrhosis was due to the shared genetic liability for alcoholism. Once the shared variance with alcoholism was considered, there was no further shared genetic liability for psychosis and cirrhosis. Our results confirm Hrubec and Omenn's conclusion that there was significantly greater concordance in MZ twins-pairs for alcoholic psychosis and cirrhosis in the NAS-NRC twins, and concordance rates remained similar to those reported 16 years earlier. In contrast, we found most of the genetic liability to organ-specific complications of alcoholism was shared with the genetic liability for alcoholism per se; only a small portion of the genetic variance of the individual complications was independent of the genetic predisposition for alcoholism.

Stroke in former prisoners of war.

OBJECTIVES: Physiological changes associated with severe or chronic stress may place susceptible individuals at risk for diseases such as stroke. METHODS: A cohort of World War II veterans consisting of former prisoners of war (POWs) and controls was studied. Data were from a follow-up examination in 1986 that included a standardized history, comprehensive examination, and psychiatric interview. RESULTS: Of former POWs, 9.3% (44 of 475) reported strokes compared with 1.2% (1 of 81) for other World War II veterans. The relative risk for this association was 7.50 (95% confidence interval [CI], 1.05 to 53.7; chi(2) = 6.00, 1 df). There was no difference in the prevalence of hypertension or diabetes. Among the 475 former POWs, 12.7% (20 of 158) of those with posttraumatic stress disorder had strokes, compared with 7.6% (24 of 317) without posttraumatic stress disorder (relative risk, 1.67; 95% CI, 0.95 to 2.93; chi(2) = 3.25, 1 df). CONCLUSIONS: There appears to be an association between stroke and being a former POW. Our findings may begin to define a new class of stroke risk factors and extend our understanding of interactions between stress and disease.

Importance of cerebrovascular disease in studies of myocardial infarction.

BACKGROUND AND PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: Our results suggest that stroke, in addition to myocardial infarction, should be considered as an outcome in clinical investigations of ischemic heart disease.

Twenty-four year mortality in World War II US male veteran twins discordant for cigarette smoking.

BACKGROUND: This study was undertaken to test the constitutional hypothesis which attributes the association of tobacco smoking with morbidity and mortality to genetic predispositions to smoking and/or disease. METHODS: Subjects were World War II veterans, born in the US between 1917 and 1927, and surveyed at mean age 47 for present and past smoking habits. Twenty-four year mortality follow-up data were available for 1515 male twin pairs discordant for lifelong cigarette smoking. Using the first or only death of a smoking-discordant pair, 24-year relative risks of mortality were calculated by zygosity, cause of death, amount smoked, and age at death. RESULTS: We found that active smokers at baseline, regardless of zygosity, had a higher risk of death than their co-twins who had never smoked or quit smoking (monozygotic pairs: relative risk [RR] = 2.5; 95% confidence interval [CI] : 1.3-6.1 and RR = 1.7; 95% CI : 1.2-2.5; dizygotic pairs: RR = 2.4; 95% CI : 1.4-3.8 and RR = 2.0; 95% CI : 1.7-3.3). The elevated risk of death among smokers was due to deaths from lung cancer (monozygotic pairs: RR = 5.0; 95% CI: 2. 6-15.0; dizygotic pairs: RR = 11.0; 95% CI : 4.3-45.0) or deaths from cardiovascular diseases (monozygotic pairs: RR = 3.9; 95% CI : 1.9-115; dizygotic pairs: RR = 2.8; 95% CI : 1.7-4.9). Apart from these findings the relationship of smoking with all-cause mortality was stronger for earlier/younger deaths and for heavy to moderate smoking. CONCLUSIONS: The present results, from the largest and longest-studied series of smoking-discordant twins negate the constitutional hypothesis that genetic or early shared familial influences underlie the significant association between tobacco smoking and premature mortality.

Vital status ascertainment through the files of the Department of Veterans Affairs and the Social Security Administration.

Veterans of US military service are a valuable resource for epidemiologic studies, and the Department of Veterans Affairs (VA) files provide an effective way to gather mortality information on veterans, so long as these files provide reasonably complete death reporting. To determine the completeness of VA death reporting, we assembled an independent sample of known veteran deaths among males born between 1936 and 1955 and assessed the performance of VA death reporting in this sample. We also compared VA death ascertainment to Social Security Administration (SSA) ascertainment. Based on the more than 4300 deaths in our study, we found VA death reporting to be approximately 90% complete by itself and 96% complete when used in conjunction with SSA death reporting. In addition, we found no evidence that VA death reporting changed substantially after passage of the Omnibus Budget Reconciliation Act of 1981, which limited eligibility for VA death benefits. Because veterans make up a large segment of the US population, our findings have particular relevance for studies in which mortality is a primary end point.