The response rate to the mailed questionnaires was 62.8% for subjects who could still be contacted (alive with known address). Approximately 3% of participants could not be located and 4% were deceased. Figure illustrates the tracking of questionnaires mailed out to participants. The 11,166 with dietary information ranged in age from 18 to 98 years (mean 54.9 years) and 6821 (61%) were female. Demographic characteristics of the dietary cohort and a comparison with non-responders are summarized in Table . Responders were more likely to be female, older, and never smokers.
Diagram of DHQ mailing for PMRP dietary cohort as of September 16, 2009. The diagram includes participants enrolled on or before 2/3/09. *nursing home and non-English speaking, **too many missing fields on the DHQ
Descriptive characteristics of the dietary cohort and comparison with non-responders
Dietary intake varied by age, gender, smoking and the E4 allele. Trends seen within data are statistically significant, unless otherwise noted. Table compares the percent use of various supplements between females and males of different age groups. The percent use of supplements for females increases as age group increases. Over fifty percent of women in each age group consume supplements; similar trends are seen for males. When comparing males and females in the same age group, the percent-use of the various supplements is lower in males than in females. Vitamin C supplements are consumed most frequently by both females and males.
Percent use of supplements by gender and age in the Personalized Medicine Research Project
Tables and compare the dietary intake between different age groups of females (Tables ) and males (Table ). Supplement-use summaries for the subset who use supplements are listed at the bottom of each table. The results suggest that with increasing age in females, food energy, total fat, cholesterol, protein, and alcohol intake decreases. Conversely, as women age, the average supplement intake increased. Similar trends were observed in males, regarding the mean and median intake of food energy, total fat, cholesterol, protein, alcohol, and supplement intake.
Dietary intake in females by age in the Personalized Medicine Research Project
Dietary intake in males by age in the Personalized Medicine Research Project
Tables , and illustrate supplement use stratified by age group, gender, smoking, and E4 allele status. Comparing females on smoking status alone, the nonsmokers generally consume more dietary supplements throughout all age groups. This similar trend is seen in males as well. The data show, once again, that females had more supplement use percentages than males when comparing relative age groups. Differences in supplement use are seen between those that have the E4 allele and those that do not. In the nonsmoking females, those with the E4 allele had higher supplement intake than nonsmokers without E4. Current smoking females with E4 have a higher supplement intake than those without E4. This trend is relatively consistent throughout all age groups in females. The data show some inconsistencies between males and females. In nonsmoking males between ages 18-39, those with E4 have higher percent use than those without E4; in the same age group, smokers without the E4 allele had higher use of supplements. In the other two age groups, nonsmoking males with E4 have lower percent use of supplements than those without E4. Current smoking males with E4 had a lower percent use than those without E4. This trend is seen in current smokers among each age group in males. Supplement use by E4 differed between genders. In general, females with E4 had higher supplement use percentages, and males with E4 had lower supplement use percentages compared to those without E4.
Percent use of supplements by gender, smoking status, and E4 in subjects aged 18-39 in the Personalized Medicine Research Project
Percent use of supplements by gender, smoking status, and E4 in subjects aged 40-59 in the Personalized Medicine Research Project
Percent use of supplements by gender, smoking status, and E4 in subjects aged 60 and older in the Personalized Medicine Research Project
Table compares the dietary intake between smoking and nonsmoking females and males. For females, the data suggest that the dietary intake for food energy, total fat, cholesterol, alcohol, vitamin E (mg ATE CSFII), selenium, and lycopene was higher in smokers versus nonsmokers. Furthermore, the dietary intake for vitamin A (IU CSFII), vitamin A (mcg RE CSFII), and vitamin C was higher in nonsmokers than in smokers. No differences were seen in supplement intake between the two groups. Differences can also be seen between smokers and nonsmokers when comparing 25% and 75% quartile values. The results regarding smoking and dietary intake for males were not statistically significant. Nonsmokers generally consumed healthier diets, as evidenced by using more supplements, consuming higher dietary vitamin C, and consuming less alcohol.
Dietary intake by gender and smoking status in the Personalized Medicine Research Project. The total number of participants who smoked and never smoked is indicated by "N" beneath the respective category.
Tables and illustrate the supplement intake between females (Table ) and males (Table ) stratified by having the E4 allele or not. The data suggest that females with the E4 allele have higher supplement intake than those without it; however, when looking at the "supplement users only" data, there is little to no difference by E4 status. As for males, the data suggest that those without the E4 allele have higher supplement intake. With some exceptions, the same general trend is seen within the "supplement users only" data.
Supplement intake by APOE4 genotype in females in the Personalized Medicine Research Project
Supplement intake by APOE4 genotype in males in the Personalized Medicine Research Project