Eiichi Uchida

Socioeconomic factors affecting the longevity of the Japanese population: a study for 1980 and 1985.

The effects of urbanisation, low income and rejuvenation of the population on life expectancy at birth and at 20, 40 and 65 years of age for males and females in Japan were examined twice, in 1980 and 1985. For males, urbanisation was the major factor determining life expectancy at birth and at age 20 years, and low income was the key determinant of decreased life expectancy except at 65 years of age. For females high income was the factor significantly decreasing life expectancy at 65 years of age in 1980, and rejuvenation of the population inversely influenced life expectancy except at birth in 1985. Life expectancy for all age groups in 1985 was significantly longer than in 1980 for both males and females.

Socioeconomic factors affecting marriage, divorce and birth rates in a Japanese population

The effects of low income, urbanisation and young age population on age-adjusted rates of first marriage, divorce and live birth among the Japanese population in 46 prefectures were analysed by stepwise regression for 1970 and for 1975. During this period, Japanese society experienced a drastic change from long-lasting economic growth to serious recession in 1973. In both 1970 and 1975, the first marriage rate for females was inversely related to low income and the divorce rates for both males and females were positively related to low income. The live birth rate was significantly related to low income, urbanisation and young age population only in 1975. The first marriage rate for females and the divorce rates for both sexes increased significantly but the first marriage rate for males and live birth rate significantly decreased between 1970 and 1975. These findings suggest that low income was the essential factor affecting first marriage for females and divorce for males and females.

Assessment of Central, Peripheral, and Autonomic Nervous System Functions in Lead Workers: Neuroelectrophysiological Studies1

To assess the effects of lead on central, peripheral, and autonomic nervous systems, the visual-, short-latency somatosensory-, and brainstem auditory-evoked potentials (VEP, SSEP, and BAEP), event-related potential (P300), distribution of nerve conduction velocities (DCV), and electrocardiographic R-R interval variability (CVRR), together with conventional median and radial nerve conduction velocities (NCV), were measured in the lead workers. The lead workers consisted of 22 gun metal foundry workers occupationally exposed to lead, zinc, and copper. In the lead workers with blood lead concentrations below 65 μg/dl, the latencies of the VEP (from the retina to the visual cortex), SSEP (from the brachial plexus to the brainstem), and P300 (which reflects cognitive function) were significantly prolonged when compared with the sex- and age-matched controls. All these latencies and the BAEP latencies (from the cochlear nerve to the brainstem) were significantly correlated with the indicators of lead absorption among these workers. The CVRR (especially, a component of parasympathetic activity) was significantly depressed in the lead workers. The slower (V10) velocity of the DCV, the motor, and sensory NCVs were also significantly slowed. These findings suggest that lead affects not only peripheral nerve but also the central and autonomic nervous functions at a subclinical level; zinc may antagonize the neurotoxic effects of lead.