Mortality from Parkinson's disease and other causes in men who were prisoners of war in the Far East

Background During World War II, more than 140 000 Allied prisoners of war ( POWs) were held captive by the Japanese in conditions of extreme privation. There have been concerns that the survivors are at increased risk of degen erative neurological disorders, especially Parkinson's disease. We assemble d a cohort of British ex-POWs and analysed their mortality in a 46-year fol low-up study. Methods Using records held by the War Pensions Agency, we abstracted data o n 11915 British former POWs. 11134 men were traced, and observed numbers of deaths between 1952 and 1997 were compared with those expected from nation al rates for the male population of England and Wales. Standardised mortali ty ratios (SMR) were calculated. Findings Overall, mortality was lower than expected (7474 deaths vs 8796.2 expected; SMR 0.85 [95% CI 0.83-0.87]). Death rates from Parkinson's diseas e among the former POWs were slightly below the national average, though th is difference was not statistically significant (35 deaths vs 43.2 expected ; SMR 0.81 [0.56-1.13]). A similar pattern was seen for other degenerative neurological disorders (motorneuron disease 0.62 [0.31-1.11], multiple scle rosis 0.88 [0.42-1.61], and dementia 0.88 [0.68-1.11]). The former POWs had significantly lower than expected mortality from all major causes of death (ischaemic heart disease 0.81 [0.78-0.85], cerebrovascular disease 0.88 [0 .81-0.95], all malignant neoplasms 0.92 [0.88-0.95], and respiratory diseas e 0.79 [0.74-0.85]). They also had below average rates of death from tuberc ulosis (0.44 [0.26-0.71]) and suicide (0.77 [0.57-1.02]), though the latter relation was not statistically significant. Mortality from diseases of the liver was increased (chronic liver disease and cirrhosis 1.68 [1.28-2.17], primary carcinoma of the liver 2.42 [1.75-3.26]). Interpretation There is little evidence that men who were POWs in the Far E ast have higher rates of death than the male population generally. The only exception is diseases of the liver, which may be due to infection with hep atitis B or C virus during captivity. Death-certification data cannot provi de a complete picture of physical and mental health, but the period of seve re malnutrition, frequent infections, exhaustion, and intense psychological stress seems not to have increased susceptibility to neurodegenerative dis ease.