Longitudinal hair chromium profiles of elderly subjects with normal glucose tolerance and type 2 diabetes mellitus

Abstract

Longitudinal hair chromium (H-Cr) profiles in a group of patients with type 2 diabetes mellitus (n = 59; age, 62 ± 9 years) and healthy elderly (control) subjects (n = 49; age, 59 ± 10 years) matched by age and sex were measured by solid sampling electrothermal atomic absorption spectrometry, providing data on the magnitude of variation of Cr content along the hair length. H-Cr average (H-Cr av) and H-Cr proximal (H-Cr pr) ., relating to the average Cr content of the whole hair and the proximal 3-mm hair length, respectively, were also obtained. No significant difference between the healthy and diabetic group was found in mean H-Cr av or H-Cr pr contents (248 ± 108 vs 247 ± 143 and 233 ± 98 vs 278 ± 195 ng/g, respectively. However, women in the control group had significantly lower H-Cr values ( P < .01) compared with men, but this difference was absent in the diabetic population. The distribution of log H-Cr pr values in the control population displayed a Gaussian shape, in contrast to the substantially wider distribution, skewed toward lower H-Cr pr values, observed in the diabetic group. The magnitude of variation in H-Cr content in the patient group over an interval of approximately 2 to 3 months (time of growth of the hair sampled) was found to be a factor of more than 2 larger than that in the control population (± 58% vs ± 26%). A strong relationship ( R = 0.656; P < .01) between log H-Cr pr and log fasting plasma Cr was observed in the diabetic group (n = 20). The mean fasting plasma Cr value of this group was 0.41 ± 0.10 μg Cr per liter. No correlation between H-Cr av. and duration of diabetes was observed. A strong positive association was observed in the control population between H-Cr pr and fasting plasma insulin (n = 22; R = 0.6157; P < .01), and H-Cr pr and fasting plasma glucose (n = 24; R = 0.4118; P < .05), which is indicative of the interrelation of these parameters. In the control population, H-Cr av showed a slight decrease with age (n = 54; R = 0.2691; P < .05), which is assumed to be the result of increased insulin resistance caused by various age-associated factors including Cr deficiency. None of the above relationships was significant in the diabetic group. Evidence is presented that justifies the assumption that the longitudinal H-Cr profile resembles the variation in Cr metabolic rate over the time span of growing hair, which is not appreciably affected by external contamination. This suggests that glucose intolerance (type 2 diabetes mellitus) is an important factor that disturbs Cr metabolism.