Among Zik covariates, education (y) was centered at 16y (approximate mean

Among Zik covariates, education (y) was centered at 16y (approximate mean for BLSA), BMI at 25 kg/m2, total energy intake at 2000 kcal/d, Agebase at 50 y, and Yearbase at 2000. Xija are the main predictor variables: “Quinagolide (hydrochloride) web caffeine centered at 0 mg/d,” “NAS centered at 10,” and “alcohol centered at 10 g/d”; z0i and z1i are level-2 disturbances; and eij is the within-person level-1 disturbance. In a sensitivity analysis, alcohol was entered as categorical variable and interacted as such with time elapsed: 0 = 14 to 28 g/d, 1 = <14 g/d, 2 = >28 g/d. Thus, having lower and higher than moderate consumption was compared with moderate consumption. Estimated BX795 site parameters with SE and P values reflected rate of cognitive change over time (g 10), the effects of caffeine and alcohol intakes and NAS on baseline cognitive performance (time = 0) (g01, g 02, and g 03; g 031 and g 032 for categorical alcohol), and effects of caffeine and alcohol intakes and NAS on annual rate of cognitive change over time (g 11, g12, and g 13; g 131 and g 132 for categorical alcohol). Analysis was presented for the overall sample and was further stratified by sex and Agebase (<70 y vs. 70 y). The effect modification by sex and Agebase was tested by including additional interaction terms in the ``overall population'' model (e.g., Agebase3 caffeine and Agebase3 caffeine 3 time, separately). We used a 2-stage Heckman selection model adjusting for bias because of nonrandom participant selection for final analyses (80,81). We further estimated cognitive test scores and plotted their predicted means against time, with Agebase set alternatively at 50 y and 70 y. Each exposure was examined separately controlling for the other covariates. Caffeine intake was alternatively set at 0 mg/d vs. 300 mg/d; alcohol intake at 10 g/d vs. 50 g/d; and NAS at 5 vs. 15. Thus, cognitive performance trajectories for the hypothetical population with set covariate distribution was examined over time and compared by exposure level to illustrate direction and magnitude of fixed effects g 0a and g 1a. Type I error was set at 0.05 for each of the 3 exposure variablerelated hypotheses. Adjustment for multiple testing reduced the type I error to 0.05/3 = 0.017, and thus only P values <0.017 were considered statistically significant. However, type I error for 3-way interaction terms was set to 0.10 because of reduced power to detect significant associations (82).n 3 3 l 3 n 3 lResultsAs shown in Table 1, compared with men, women were generally older and had more ethnic diversity, performed better on the MMSE, and had lower prevalence of current smoking. The distribution of study characteristics by sex and data completeness is presented in Supplemental Table 1 and Supplemental Figure 1. Several key findings emerged from the time-interval, mixedeffects regression models. For most cognitive tests, younger participants at baseline performed better than older participantsTABLE 1 Baseline characteristics of participants included in the final analysis with the MMSE (global cognitive function) and dietary data available, stratified by sex, BLSA, 1962?n2 Men, n First-visit age, y Race/ethnicity Non-Hispanic white Non-Hispanic black Other First-visit education, y First-visit smoking Never smoker Former smoker Current smoker First-visit BMI, kg/m2 Energy intake, kcal/d NAS .10 (above median), Caffeine, mg/d 100?00 mg/d (1? cups of coffee), Alcohol, g/d 14?8 g/d (1? drinks), MMSE total score Women, n First-v.Among Zik covariates, education (y) was centered at 16y (approximate mean for BLSA), BMI at 25 kg/m2, total energy intake at 2000 kcal/d, Agebase at 50 y, and Yearbase at 2000. Xija are the main predictor variables: ``caffeine centered at 0 mg/d,'' ``NAS centered at 10,'' and ``alcohol centered at 10 g/d''; z0i and z1i are level-2 disturbances; and eij is the within-person level-1 disturbance. In a sensitivity analysis, alcohol was entered as categorical variable and interacted as such with time elapsed: 0 = 14 to 28 g/d, 1 = <14 g/d, 2 = >28 g/d. Thus, having lower and higher than moderate consumption was compared with moderate consumption. Estimated parameters with SE and P values reflected rate of cognitive change over time (g 10), the effects of caffeine and alcohol intakes and NAS on baseline cognitive performance (time = 0) (g01, g 02, and g 03; g 031 and g 032 for categorical alcohol), and effects of caffeine and alcohol intakes and NAS on annual rate of cognitive change over time (g 11, g12, and g 13; g 131 and g 132 for categorical alcohol). Analysis was presented for the overall sample and was further stratified by sex and Agebase (<70 y vs. 70 y). The effect modification by sex and Agebase was tested by including additional interaction terms in the ``overall population'' model (e.g., Agebase3 caffeine and Agebase3 caffeine 3 time, separately). We used a 2-stage Heckman selection model adjusting for bias because of nonrandom participant selection for final analyses (80,81). We further estimated cognitive test scores and plotted their predicted means against time, with Agebase set alternatively at 50 y and 70 y. Each exposure was examined separately controlling for the other covariates. Caffeine intake was alternatively set at 0 mg/d vs. 300 mg/d; alcohol intake at 10 g/d vs. 50 g/d; and NAS at 5 vs. 15. Thus, cognitive performance trajectories for the hypothetical population with set covariate distribution was examined over time and compared by exposure level to illustrate direction and magnitude of fixed effects g 0a and g 1a. Type I error was set at 0.05 for each of the 3 exposure variablerelated hypotheses. Adjustment for multiple testing reduced the type I error to 0.05/3 = 0.017, and thus only P values <0.017 were considered statistically significant. However, type I error for 3-way interaction terms was set to 0.10 because of reduced power to detect significant associations (82).n 3 3 l 3 n 3 lResultsAs shown in Table 1, compared with men, women were generally older and had more ethnic diversity, performed better on the MMSE, and had lower prevalence of current smoking. The distribution of study characteristics by sex and data completeness is presented in Supplemental Table 1 and Supplemental Figure 1. Several key findings emerged from the time-interval, mixedeffects regression models. For most cognitive tests, younger participants at baseline performed better than older participantsTABLE 1 Baseline characteristics of participants included in the final analysis with the MMSE (global cognitive function) and dietary data available, stratified by sex, BLSA, 1962?n2 Men, n First-visit age, y Race/ethnicity Non-Hispanic white Non-Hispanic black Other First-visit education, y First-visit smoking Never smoker Former smoker Current smoker First-visit BMI, kg/m2 Energy intake, kcal/d NAS .10 (above median), Caffeine, mg/d 100?00 mg/d (1? cups of coffee), Alcohol, g/d 14?8 g/d (1? drinks), MMSE total score Women, n First-v.