490 V. BLOOD LIPIDS 



that for women at term was reported as 35.4 microgram per cent. On the 

 other hand, the average value for vitamin A in fifty samples of cord blood 

 was found to be 27.4 microgram per cent. 



(b) Plasma Carotene and Vitamin A in Children. The most compre- 

 hensive studies on the effect of age on the carotene and vitamin A content 

 of the blood of children were made by Szymanski and Longwell. 869 These 

 workers determined the plasma carotene and vitamin A in ninety-five 

 healthy children from two days to sixteen years of age. The median 

 value (in italics) of plasma carotene in microgram per cent (including 

 minimum and maximum) were as follows: 2 days, 34 (18-61) ; 1 month, 37 

 (14-111); 2 months, 42 (7-135); 3 months, 45 (18-157); 6 months, 174 

 (49-337) , 9 months, 268 (166-592) ; 12 months, 328 (183-672) ; 15 months, 

 281 (123-581); 18 months, 253 (109-452); 21 months, 233 (96-377); 24- 

 27 months, 201 (52-391) ; 30 to 33 months, 171 (64-285) ; 3 to 4 years, 156 

 (84-281); 4.5 to 5.5 years, 150 (56-304); 6 to 7 years, 149 (40-299); 7.5 

 to 8.5 years, 147 (61-297) ; 9 to 10 years, 130 (54-286) ; 10.5 to 11.5 years, 

 117 (51-283); 12 to 13 years, 114 (63-272); and 13 to 16 years, 126 (61- 

 258). These values are in line with the ranges reported by May and col- 

 laborators, 860 for children two to twelve years of age, i.e., 140 (47 to 233 

 microgram per cent) (based upon a conversion key given by Henley et 

 al. m ), and of Krause and Pierce 862 for 179 presumably normal school 

 children, who gave values of 116 =fc 45.7 microgram per cent. They 

 also agree with the averages of Robinson et al. s63 for normal and under- 

 privileged children in Michigan from six to sixteen years old, which varied 

 between 100 and 168 microgram per cent. It would thus appear that 

 the carotene levels in the blood plasma start at minimum values, which 

 are maintained for the first three months of life, after which they rapidly 

 rise to a maximum at twelve months. Following this, the blood carotene 

 values gradually decrease until, after the age of two years, they reach a 

 level which corresponds to that noted in some of the surveys on adults. 

 The blood carotene values for the school children would seem to be lower 

 than those recorded in most tests on adults. 



Szymanski and Longwell 859 recorded the following median values (in 



869 B. B. Szymanski and B. B. Longwell, /. Nutrition, 45, 431-442 (1951). 



860 C. D. May, K. D. Blackfan, J. F. McCreary, and F. H. Allen, Am. J. Diseases 

 Children, 59, 1167-1184 (1940). 



861 T. H. Henley, M. Dann, and W. R. C. Golden, Am. J. Diseases Children, 68, 257- 

 264 (1944). 



862 R. F. Krause and H. B. Pierce, J. Nutrition, 38, 633-640 (1947). 



863 A. Robinson, M. Lesher, A. P. Harrison, E. Z. Moyer, M. C. Gresock, and C. 

 Saunders, J. Am. Dietet. Assoc., 24, 410-416 (1948). 



