Chapter 14 477 data for total hair lipids versus age is summarized in Figure 3 and compares favorably with the data of Pochi and Strauss shown in Figure 2. A box plot revealed two outliers which when rejected provided a normal distribution with a Shapiro-Wilk W of 0.978 and a p = 0.5. These data when regressed versus age provided a quadratic model with p 0.0001, root mean square error of 5.623 and an r2 of 0.387. From the model equation, the maximum for hair lipids was at age 45, corresponding to where the steep drop begins for sebum production on the foreheads of women by Pochi and Strauss, as seen in Figure 2. These effects lead into the effects of menopause on hair fibers. The effects of menopause on hair fiber lipids: Wills et al.56 showed that wax esters and squalene content (both primarily from sebum) were significantly lower in post-menopausal than pre- menopausal women. These same scientists noted that their analytical procedure could not distinguish between wax esters and cholesterol esters however, the wax ester levels are higher in adult human hair than cholesterol esters as shown by the work of Pochi et al.54 Age in years Sebum production on forehead 2.4 1.8 1.2 0.6 0 3 8 10 10 20 30 40 60 80 Males Females Figure 2 Sebum production mg lipid/10 sq cm/3 hr