@Copyright 1987 by The Humana Press Inc. All rights of any nature, whatsoever, reserved. 0163-4984/87/1200~383502.00
Use of Hair as a Biopsy Tissue for Calcium J. BACSO,' I. UZONYI,~ AND S. A. KATZ*'2
'Institute for Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary, H-4001; and 2Rutgers the State University of New Jersey, Camden NJ 08102 U.S.A.
ABSTRACT Experimental and literature values for hair calcium levels were evaluated to identify their physiological significance. The distribution of values obtained from different populations indicates that the calcium content of scalp hair reflects calcium metabolism in the body. Correlations between the hair calcium concentrations from different anatomical sites support this indication. Index Entries; Calcium, in hair; XRF; biological indicators; hair, as a biopsy tissue.
INTRODUCTION There is some controversy in the literature concerning the diagnostic significance of microelement levels in h u m a n scalp hair. On the one hand, some investigators have reported correlations b e t w e e n various diseased states and the concentrations of essential or toxic microelements in scalp hair (1-5). On the other hand, different reports identify inconsistencies in the levels of these elements in scalp hair, which are interpreted as reflecting little biological regulation of their incorporation (6-9). In this respect, one of us (10-12) has established a relationship b e t w e e n the incidence of myocardial infarction and the level of e n d o g e n o u s calcium in scalp hair, but another (13,14) has urged caution in interpreting data on the levels of the microelements in hair because of the problems associated with differentiating between those of e n d o g e n o u s origin and those of exogenous origin. For this reason, we found it necessary to *Author to whom all correspondence and reprint requests should be addressed. Biological Trace Element Research
383
VoL 12, 1987
384
Bacso, Uzonyi, and Katz
jointly evaluate the data from our respective laboratories and to come to a conclusion on the use of hair as a biopsy tissue.
MATERIALS AND METHODS In order to compare the data from our respective laboratories, careful consideration was given to the procedures used to collect and prepare the hair samples, as well as to the techniques for determining their microelement contents. The specifics regarding these procedures and techniques have been reported elsewhere (13,15). The major difference appears to be in the washing procedures; i.e., 2% acetic acid/water versus acetone/water. Using the IAEA hair standard, HH-1 (16), Bacso determined a factor of 1.27 for converting the results obtained for calcium levels in hair samples washed with 2% acetic acid/water to the acetone/water basis. The American calcium results for scalp hair washed with acetone/ water (13) were divided by this factor and evaluated as a log-normal distribution. In this form, the data were found to coincide with those obtained from Hungarian scalp hair samples washed with 2% acetic acid/water (12). Both sets of data, as well as data from Japan (17) and a current Hungarian survey, were found to show bimodal distributions, with central minima at about 700 ppm when presented in the log-normal form. These data are summarized in Table 1, in which population group I is from a screening test in Hungary (12), population group II is from a current Hungarian survey, population group III is from a Japanese environmental monitoring program (17), and population group IV is from an American study on anatomical variations (13). To evaluate the anatomical variations of calcium levels in hair identified in the American study (13) in a manner more consistent with the Hungarian investigations (10,12), the original data were divided into agematched and sex-matched cohorts. The most stable cohorts in terms of calcium scalp hair levels were in the 20-35-yr-old age group (10). Although this division reduced the total sample population by one third, it provided more homogenous groupings. The results of linear regression analysis (18) for the calcium levels in scalp and pubic hair of the agematched and sex-matched cohorts are summarized in Table 2. For the further evaluation of possible anatomical variations, samples were collected daily from the face and pubes of one Hungarian male subject. The use of samples from a single subject over an extended period of time avoided differences in calcium levels caused by biological variations between individuals and/or personal cosmetic treatments. The samples were collected with an electric shaver, pressed into 8-mm pellets, dried at 105~ for 30 min, and evaluated by XRF in vacuum, using 55Fe for excitation. It was necessary to combine the samples from 4 d in order to obtain sufficient material for the measurement of the calcium levels. The results were tabulated as milligrams of calcium/kg of hair/d for both anatomical Biological Trace Element Research
VoL 12, 1987
385
Hair Calcium Levels TABLE 1 Log-Normal Distribution of Hair Calcium Concentrations" % Of samples Population Log Ca
Group I Group II Group III Group IV
1.7/1.8 1.8/1.9 1.9/2.0 2.0/2.1 2.1/2.2 2.2/2.3 2.3/2.4 2.4/2.5 2.5/2.6 2.6/2.7 2.7/2.8 2.8/2.9 2.9/3.0 3.0/3.1 3.1/3.2 3.2/3.3 3.3/3.4 3.4/3.5 3.5/3.6 3.6/3.7 3.7/3.8
2 4 5 14 10 11 11 4 3 5 7 7 5 5 4 3 1
1 1 6 12 16 16 9 7 4 4 5 6 5 5 2 2 2
1 2 2 3 5 9 11 11 7 7 8 8 10 7 5 3
5 2 2 7 5 7 14 14 5 5 2 12 7 2 10 5
'In mg/kg.
sites. These data were also treated by linear regression analysis the calculated values are presented in Table 3.
(18), and
DISCUSSION W h e n adjusted for differences in sample preparation procedures, the log-normal distributions of calcium levels in scalp hair from Japan and from the USA match those from the Hungarian Peoples' Republic. The similarities in these distributions of scalp hair calcium levels originating from three different countries may indicate that a biological mechanism governs the incorporation of calcium into scalp hair. The linear regression analysis (18) indicates a correlation between the calcium levels in scalp hair and the corresponding calcium levels in the pubic hair on a subject-by-subject basis. The correlation is less strongly demonstrated by males than by females. The favorable correlaBiological Trace Element Research
Vol. 12, 1987
Bacso, Uzonyi, and Katz
386
TABLE 2 Linear Regression Analysis of Calcium Levels in Scalp and Pubic Hair' 20-35-yr-old age group
Males
Females
Scalp Mean + s
862 _+ 918
714 +_ 933 1139 _+ 851
Pubic Mean _+ s m y r p
578 0 423 0
Use of Hair as a Biopsy Tissue for Calcium J. BACSO,' I. UZONYI,~ AND S. A. KATZ*'2
'Institute for Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary, H-4001; and 2Rutgers the State University of New Jersey, Camden NJ 08102 U.S.A.
ABSTRACT Experimental and literature values for hair calcium levels were evaluated to identify their physiological significance. The distribution of values obtained from different populations indicates that the calcium content of scalp hair reflects calcium metabolism in the body. Correlations between the hair calcium concentrations from different anatomical sites support this indication. Index Entries; Calcium, in hair; XRF; biological indicators; hair, as a biopsy tissue.
INTRODUCTION There is some controversy in the literature concerning the diagnostic significance of microelement levels in h u m a n scalp hair. On the one hand, some investigators have reported correlations b e t w e e n various diseased states and the concentrations of essential or toxic microelements in scalp hair (1-5). On the other hand, different reports identify inconsistencies in the levels of these elements in scalp hair, which are interpreted as reflecting little biological regulation of their incorporation (6-9). In this respect, one of us (10-12) has established a relationship b e t w e e n the incidence of myocardial infarction and the level of e n d o g e n o u s calcium in scalp hair, but another (13,14) has urged caution in interpreting data on the levels of the microelements in hair because of the problems associated with differentiating between those of e n d o g e n o u s origin and those of exogenous origin. For this reason, we found it necessary to *Author to whom all correspondence and reprint requests should be addressed. Biological Trace Element Research
383
VoL 12, 1987
384
Bacso, Uzonyi, and Katz
jointly evaluate the data from our respective laboratories and to come to a conclusion on the use of hair as a biopsy tissue.
MATERIALS AND METHODS In order to compare the data from our respective laboratories, careful consideration was given to the procedures used to collect and prepare the hair samples, as well as to the techniques for determining their microelement contents. The specifics regarding these procedures and techniques have been reported elsewhere (13,15). The major difference appears to be in the washing procedures; i.e., 2% acetic acid/water versus acetone/water. Using the IAEA hair standard, HH-1 (16), Bacso determined a factor of 1.27 for converting the results obtained for calcium levels in hair samples washed with 2% acetic acid/water to the acetone/water basis. The American calcium results for scalp hair washed with acetone/ water (13) were divided by this factor and evaluated as a log-normal distribution. In this form, the data were found to coincide with those obtained from Hungarian scalp hair samples washed with 2% acetic acid/water (12). Both sets of data, as well as data from Japan (17) and a current Hungarian survey, were found to show bimodal distributions, with central minima at about 700 ppm when presented in the log-normal form. These data are summarized in Table 1, in which population group I is from a screening test in Hungary (12), population group II is from a current Hungarian survey, population group III is from a Japanese environmental monitoring program (17), and population group IV is from an American study on anatomical variations (13). To evaluate the anatomical variations of calcium levels in hair identified in the American study (13) in a manner more consistent with the Hungarian investigations (10,12), the original data were divided into agematched and sex-matched cohorts. The most stable cohorts in terms of calcium scalp hair levels were in the 20-35-yr-old age group (10). Although this division reduced the total sample population by one third, it provided more homogenous groupings. The results of linear regression analysis (18) for the calcium levels in scalp and pubic hair of the agematched and sex-matched cohorts are summarized in Table 2. For the further evaluation of possible anatomical variations, samples were collected daily from the face and pubes of one Hungarian male subject. The use of samples from a single subject over an extended period of time avoided differences in calcium levels caused by biological variations between individuals and/or personal cosmetic treatments. The samples were collected with an electric shaver, pressed into 8-mm pellets, dried at 105~ for 30 min, and evaluated by XRF in vacuum, using 55Fe for excitation. It was necessary to combine the samples from 4 d in order to obtain sufficient material for the measurement of the calcium levels. The results were tabulated as milligrams of calcium/kg of hair/d for both anatomical Biological Trace Element Research
VoL 12, 1987
385
Hair Calcium Levels TABLE 1 Log-Normal Distribution of Hair Calcium Concentrations" % Of samples Population Log Ca
Group I Group II Group III Group IV
1.7/1.8 1.8/1.9 1.9/2.0 2.0/2.1 2.1/2.2 2.2/2.3 2.3/2.4 2.4/2.5 2.5/2.6 2.6/2.7 2.7/2.8 2.8/2.9 2.9/3.0 3.0/3.1 3.1/3.2 3.2/3.3 3.3/3.4 3.4/3.5 3.5/3.6 3.6/3.7 3.7/3.8
2 4 5 14 10 11 11 4 3 5 7 7 5 5 4 3 1
1 1 6 12 16 16 9 7 4 4 5 6 5 5 2 2 2
1 2 2 3 5 9 11 11 7 7 8 8 10 7 5 3
5 2 2 7 5 7 14 14 5 5 2 12 7 2 10 5
'In mg/kg.
sites. These data were also treated by linear regression analysis the calculated values are presented in Table 3.
(18), and
DISCUSSION W h e n adjusted for differences in sample preparation procedures, the log-normal distributions of calcium levels in scalp hair from Japan and from the USA match those from the Hungarian Peoples' Republic. The similarities in these distributions of scalp hair calcium levels originating from three different countries may indicate that a biological mechanism governs the incorporation of calcium into scalp hair. The linear regression analysis (18) indicates a correlation between the calcium levels in scalp hair and the corresponding calcium levels in the pubic hair on a subject-by-subject basis. The correlation is less strongly demonstrated by males than by females. The favorable correlaBiological Trace Element Research
Vol. 12, 1987
Bacso, Uzonyi, and Katz
386
TABLE 2 Linear Regression Analysis of Calcium Levels in Scalp and Pubic Hair' 20-35-yr-old age group
Males
Females
Scalp Mean + s
862 _+ 918
714 +_ 933 1139 _+ 851
Pubic Mean _+ s m y r p
578 0 423 0
