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

Abstract

During World War II, more than 140000 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 degenerative neurological disorders, especially Parkinson's disease. We assembled a cohort of British ex-POWs and analysed their mortality in a 46-year follow-up study. Using records held by the War Pensions Agency, we abstracted data on 11915 British former POWs. 11134 men were traced, and observed numbers of deaths between 1952 and 1997 were compared with those expected from national rates for the male population of England and Wales. Standardised mortality ratios (SMR) were calculated. 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 disease among the former POWs were slightly below the national average, though this 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 sclerosis 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 disease 0.79 [0.74-0.85]). They also had below average rates of death from tuberculosis (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]). There is little evidence that men who were POWs in the Far East 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 hepatitis B or C virus during captivity. Death-certification data cannot provide a complete picture of physical and mental health, but the period of severe malnutrition, frequent infections, exhaustion, and intense psychological stress seems not to have increased susceptibility to neurodegenerative disease.