Masaki Moriyama

Renal Tubular Function after Reduction of Environmental Cadmium Exposure: A Ten-year Follow-up

A prospective follow-up study was carried out to assess the prognosis of renal tubular function after reduction of environmental cadmium exposure. Time-related changes in urinary beta 2-microglobulin and cadmium excretion were followed from 1979 to 1989 in 102 residents of a cadmium-polluted area in Nagasaki, Japan. The average dietary cadmium intake among the study population was more than 200 micrograms/d in 1969, which decreased to approximately half that amount in 1983 because cadmium-polluted paddy fields were replaced with new soil in 1981. The geometric mean urinary beta 2-microglobulin concentration for 28 subjects aged 40 y or older in 1979 increased from 1,135.8 micrograms/g creatinine in 1979 to 1,999.7 micrograms/g creatinine in 1989. A similar tendency was also observed in 16 subjects with urinary beta 2-microglobulin concentrations greater than 1,000 micrograms/g creatinine in 1979, although the statistical significance of the difference did not reach the 5% level, probably because of the small sample size. In 48 persons examined in 1982, 1986, and 1989, the geometric mean of urinary cadmium concentration decreased from 8.49 micrograms/g creatinine in 1982 to 6.03 micrograms/g creatinine in 1989. The tendency for increasing beta 2-microglobulin excretion observed in the present study could not be explained by aging alone. Thus, it was concluded that renal tubular dysfunction caused by environmental cadmium was irreversible and slowly progressive, even after reduction of exposure. Six of 8 subjects who had severe renal dysfunction and who were included in the study died before 1986 and could not be followed. The implication of loss of subjects because of death is also discussed.

Follow up study of renal tubular dysfunction and mortality in residents of an area polluted with cadmium.

A retrospective cohort study was conducted to investigate the association between cadmium induced renal tubular dysfunction and mortality. A total of 230 subjects aged 40 or older and living in a cadmium polluted area in Kosaka Town, Akita Prefecture, Japan, were studied at least once between 1975 and 1977 and again in 1990. Urinary beta 2-microglobulin and total amino nitrogen concentrations were significantly related to mortality from all causes in women. The finding supports the idea that cadmium induced kidney damage is a factor associated with mortality in a general population exposed to environmental cadmium.

Growth and motor performance of black and white children 6–10 years of age: A multivariate analysis

The relationships between anthropometry and physical performance were considered in 439 Black and 386 White children, 6 through 10 years of age. Anthropometric dimensions included weight, statute, sitting height, six skeletal breadths, three limb circumferences, and three skinfolds. Performance variables included four static strength and three motor tasks. Principal components analysis was used to reduce the anthropometric dimensions to four components for each age group (sexes combined) within race. Only two components had eigenvalues greater than 1 in all age and both racial groups. The first two components accounted for 81 to 87% of the variance in anthropometry in Black children and for 79 to 85% of the variance in White children. Path coefficients from sex directly to performance and the products of path coefficients from sex to the first or second principal component to performance were computed for each strength and motor task in each age and race group. With few exceptions, path coefficients from sex directly to performance were negative and suggested an effecct of sex on performance which is independent of anthropometric characteristics.