Selective migration by birthweight.
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Biomedical subjects
Publications and source records attributed to C N Martyn.
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In a case-control study of 214 patients with multiple sclerosis, recall of infectious mononucleosis in subjects seropositive for Epstein-Barr viral capsid antigen was associated with a relative risk of 2.9 (95% CI 1.1 to 7.2). Those who reported having infectious mononucleosis before the age of 18 years had a relative risk of multiple sclerosis of 7.9 (95% CI 1.7 to 37.9). The pathogenesis of multiple sclerosis may involve an age-dependent host response to Epstein-Barr virus infection.
The combination of an ageing population, an exponential increase in the incidence of dementing illness with age, and the high demands that demented patients place on health care resources makes Alzheimer's disease a major public health issue. So far, epidemiologists have made better progress in quantifying the frequency of the disease than in identifying strong risk factors, but evidence is accumulating to implicate environmental exposure to aluminium in the aetiology. The finding of a geographical correlation between death rates from dementia and water aluminium concentrations in Norway has since been replicated in several other surveys. Although ecological studies of this type should be interpreted cautiously, the association between Alzheimer's disease and aluminium in drinking water may prove to be an example of a potentially important biological effect of aluminium.
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To investigate a possible link between subclinical infection with poliovirus in childhood and increased risk of motor neuron disease in adult life, environmental determinants of infection in early life were compared in 98 cases of motor neuron disease and 335 age and sex matched controls. A weak but consistent relation was found between motor neuron disease and factors in the childhood environment known to increase likelihood of enteric infection. Relative risks associated with spending the first 10 years of life in a house without domestic amenities such as a bathroom, running hot water or flushing lavatory, living in overcrowded conditions, frequent changes of address or having a sibling with paralytic poliomyelitis were all greater than unity, although only those for absence of running hot water and frequent changes of address were statistically significant.
In England and Wales there is a strong geographical relation between current mortality from chronic bronchitis and emphysema in adults and infant mortality from bronchitis and pneumonia 50 years ago. Follow-up studies of infants and children show that certain pulmonary infections cause persisting abnormalities of lung function. This suggests that infection of an organ system during a period of rapid growth may have permanent deleterious effects. Long-term consequences of infection may also depend on age-related differences in the host response. The relationship between age of infection with hepatitis B virus and the likelihood of becoming a chronic HBsAg carrier is an example of this. Evidence that the common communicable diseases of childhood tend to have occurred late in cases of multiple sclerosis hints at similar mechanisms in this disease. The current patterns of motor neuron disease mirror the epidemiology of poliovirus infection 40 years ago both in geographical distribution and in changes over time. The same neuronal populations are affected in both these conditions; is there a causal link?
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The prevalence of radiological criteria of chronic sinus infection was compared in 42 cases of clinically definite or laboratory supported definite multiple sclerosis and 84 controls. No increase in relative risk of multiple sclerosis associated with the presence of chronic sinus infection was observed (odds ratio 1.2, 95% CI 0.5 to 3.1). The maxillary sinus was infected more often than the other paranasal sinuses but there was no difference in the distribution of infection within the sinuses between cases and controls. These results do not confirm an earlier report of an association between chronic sinus infection and multiple sclerosis.
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41 forestry workers, who had a high occupational risk of tick-bites, were screened for antibodies to Borrelia burgdorferi by ELISA and western blotting techniques, and questioned about possible symptoms of Lyme disease. Antibodies were detected in 10 of the 40 men who had been bitten by ticks. Definite symptoms of Lyme disease, in the form of erythema migrans, were reported by only 2 workers and none had a history of neurological illness.
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In a survey of eighty-eight county districts within England and Wales, rates of Alzheimer's disease in people under the age of 70 years were estimated from the records of the computerised tomographic (CT) scanning units that served these districts. Rates were adjusted to compensate for differences in distance from the nearest CT scanning unit and for differences in the size of the population served by the units. Aluminium concentrations in water over the past 10 years were obtained from water authorities and water companies. The risk of Alzheimer's disease was 1.5 times higher in districts where the mean aluminium concentration exceeded 0.11 mg/l than in districts where concentrations were less than 0.01 mg/l. There was no evidence of a relation between other causes of dementia, or epilepsy, and aluminium concentrations in water.
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Aluminium is present in senile plaques and in neurofibrillary tangle-bearing neurones in brains of cases of Alzheimer's disease. Evidence linking aluminium absorption to calcium metabolism prompted a case-control study of physiological markers of calcium homeostasis in patients with Alzheimer's disease. Mean plasma 25-hydroxyvitamin D concentration was lower in cases than in controls but no difference in median parathyroid hormone concentrations or other evidence of altered calcium metabolism was found. The difference in 25-hydroxyvitamin D concentrations may be secondary to differences in exposure to sunlight.
Past notification rates for poliomyelitis show a close geographical relation with current mortality from motoneuron disease in England and Wales. The increasing rate of poliomyelitis during the first half of this century and its predilection for affluent places and families were unique amongst infectious diseases. The unusual epidemiology of poliomyelitis is now being paralleled by motoneuron disease. These observations provide new evidence for a causal connection between the two conditions.
Nuclear magnetic resonance (NMR) imaging has been used to visualise a localised area of demyelination in the dorsal pons of a patient who presented with an unusual disorder of eye movements, namely, the one-and-a-half syndrome. Judged clinically the patient made a nearly complete recovery, but little change was apparent in the NMR image six months later.
Fewer than 25% of people diagnosed during life as being demented were found to have this diagnosis coded as the underlying cause of death. In a sample of deaths certified as due to dementia the majority were found to have occurred in long-stay institutions. This distorts the geographical pattern of mortality because the Office of Population Censuses and Surveys (OPCS) considers these institutions to be the patient's usual address six months after his admission. Analysis of all certified deaths from dementia during 1968-78 by place of residence shows that areas with a significantly high SMR usually contain a large psychiatric hospital. Changes in diagnostic fashion and in the procedure by which OPCS selects the underlying cause of death have also affected numbers of deaths coded as dementia. Death certificate data are unlikely to be useful in examining either geographical variation or time trends in rates of dementia.