The Effects of Aging on Hair–More Than Just Amount 456 against a light background of gray hair than light hairs against a light gray background, or does this effect involve the cessation of production of pheomelanin (reddish-blonde pigment) versus eumelanin (brown-black pigment) in the melanocytes? We believe this effect is more likely due to perception, or the former effect rather than the latter. A second large study including graying of hair: The second large study on graying with respect to age is the Copenhagen city heart study by Schnohr et al.9 The authors of this study do not specify racial characteristics of their subjects however, because of the location, it may be assumed that the subjects are largely or totally Caucasian. One advantage to the Copenhagen study is that it contained large numbers (13,000 total subjects 5,837 men and 7,163 women). The disadvantages of this study are that the age groups were in 10-year increments and did not include any subjects less than 30 years of age. In addition, the authors separated out those subjects who dyed their hair but did not determine the grayness of hair on those subjects. The Copenhagen study separated all subjects into those with no gray hair, those with little gray hair, moderate gray hair, and total gray/white hair, and also those with dyed hair and those with wigs. To consider all of the data, we assumed that the percentage of gray-haired subjects in the dyed hair group was the same as in the non-dyed hair group and added the two together. With this assumption and combining the data of men and women, the data of % any gray and % total or complete gray correspond well with the data of Keogh and Walsh. The differences were generally within ± 2%. These data are summarized in Table 2 in terms of the percentages of little gray, moderate gray, and total gray. Best estimates on % little gray, % moderate gray, and % total gray in 5-year age increments: To see if the data from these two large studies could be combined and to look more carefully at graying in 5-year increments, in effort to derive more meaningful results, we examined the data of these two studies in tandem. Plots were made