In a retirement community group of 73 relatively fit elderly white persons, a cross-sectional study of 53 different blood tests was conducted. The five test categories for blood values were hematology, chemistry, thyroid function, protein electrophoresis, and immunology. Fifteen percent of the blood findings were outside the range accepted as normal by the examining laboratories. Most of the subjects showed between 5 and 10 "abnormal" values within the five test categories. Since the findings were fairly predictable in view of the patho-anatomic changes that accompany aging, and since the manifestations of disease were at most subclinical, only minor alterations in individual management were needed. Subsequent appropriate clinical re-evaluation of these subjects during a six-month follow-up revealed no striking changes. It would appear that the ranges of "normal" reference values may need to be expanded. Although cross-sectional laboratory studies are useful, longitudinal studies seem essential if clinicians are to attain a more valid perspective.
Photon absorption measurements of forearm bone density in 196 insulin-dependent patients, age 6--26 years, were compared with findings in 124 controls. Expected density, gm. Ca/cm.2 bone width (M/W), was calculated from regressions of M/W on ulnar length for white and black male and female controls. There were no significant correlations between M/W differences from expected and serum Ca, Mg, P, or alkaline phosphatase levels, estimated physical activity level, insulin dosage, or the presence of joint contracture. White females averaged 8.2 per cent (+/- 1 S.E.M.) loss of M/W, as against white male average loss of 4.7 per cent +/- 1 and black female loss of 2 per cent +/- 2 (p less than 0.001); the black male population was too small for separate analysis. M/W loss greater than 10 per cent was seen in 29 per cent of white males, 19 per cent of blacks, and 48 per cent of white females (p less than 0.02). When the groups were further divided into those with duration of diabetes less than or equal to five years and those with duration greater than five years, significant reduction in M/W average loss over time was seen with white females (10.6 per cent +/- 1.2 to 3.7 per cent+/- 1.5, p less than 0.0001). Expression of this defect in bone mineralization is controlled by race and sex acting independently of each other.
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