Masami Senma

Urinary β2-microglobulin Concentration and Mortality in a Cadmium-polluted Area

A 9-y follow-up study of 3,178 persons who lived in a cadmium-polluted area was conducted to assess the influence of environmental cadmium exposure on long-term outcome. The standardized mortality ratios of the urinary beta 2-microglobulin-positive subjects (> 1,000 micrograms/g creatinine) of both sexes were higher than those of the general Japanese population, whereas the cumulative survival curves were lower than those of the urinary beta 2-microglobulin-negative group. A significant association was also found between urinary beta 2-microglobulin and mortality, using a Coxs proportional hazards model. Moreover, mortality rates increased in proportion to increases in the amount of urinary beta 2-microglobulin excreted. These results suggest that the prognosis for cadmium-exposed subjects with proximal tubular dysfunction is unfavorable. The mortality rate tended to become higher as the severity of renal dysfunction progressed.

High mortality and shortened life-span in patients with itai-itai disease and subjects with suspected disease

A follow-up study was conducted from 1967 to 1987 for patients diagnosed as having itai-itai disease, subjects who were suspected of having the disease, and controls. Ninety-five subjects per category were selected after matching for age, sex, and residential area. The cumulative survival rate of the patients who had a definite diagnosis of itai-itai disease was significantly lower than that of the control group in every period after the first 3 y. The cumulative survival rate of the subjects who were suspected of having itai-itai disease and who had severe renal dysfunction due to cadmium pollution was significantly lower than that of the control group. These results demonstrate (1) the enduring negative influence of itai-itai disease on prognosis and (2) that the cadmium pollution-induced renal disorder adversely affects the health of the inhabitants of a cadmium-polluted area.

Plasma insulin and blood pressure in normotensive Japanese men with normal glucose tolerance

Objective To determine whether blood pressure within the normal range is associated with plasma insulin concentration in a Japanese population with normal glucose tolerance. Methods We studied 491 normotensive Japanese men with normal glucose tolerance, who had never been treated with antihypertensive medications. Plasma glucose and insulin response during a 75-g oral glucose-tolerance test, blood pressure, body mass index, serum lipids, alcohol consumption and smoking status were obtained. The subjects were divided into quartiles according to mean blood pressure level (< 79, 79–84, 85–91 and ≥92 mmHg). To eliminate possible confounding factors, analysis of covariance was also performed. Results In univariate analyses the plasma insulin response after an oral glucose load, especially after 60min, was significantly related to blood pressure level. Plasma glucose was related to blood pressure level only at fasting. When adjusted for age, body mass index, plasma glucose response and alcohol consumption, plasma insulin concentrations after 30 and 60min in the highest quartile were significantly higher than those in the lowest quartile. Conclusions: Blood pressure was significantly and independently related to plasma insulin level after an oral glucose load in normotensive Japanese men with normal glucose tolerance. The results suggest that the relationship between blood pressure and insulin resistance already exists in a prehypertensive state even in a lean Asian population.