The final analysis in Table 4 addressed Hypothesis 4 by evaluating main and interaction effects for numbers of ARBs across eight time points using a 3 ethnic groups by 2 sexes by 2 LR categories by 8 time points mixed-design ANOVA that controlled for maximum drinks while using education group as a covariate. For all analyses, missing data were handled through a maximum likelihood procedure . At baseline, the 398 eligible participants were 18-year-old UCSD freshmen, of whom 62% were female with 40% EA, 20% Hispanic, and 41% of Asian descent . Table 2 presents the numbers of subjects across combinations of ethnicities, sex, and LR groups. The SRE values averaged 4 drinks across four possible effects actually experienced the first five times they drank. In the prior month, these students consumed on average 6 maximum and 4 usual drinks per occasion, with 4 drinking occasions per month. At baseline, 21% noted having experienced an ARB in the prior month, with an average of 0.33 such episodes . About 40% had used cannabis the prior month, and 87% were in the active intervention group in the prevention study. Table 3 presents statistical analyses associated with the 3 figures, while Table 4 shows results of a mixed-design ANOVA for the overall statistical analysis regarding Hypothesis 4.Figure 1 presents the average number of ARBs the month before each assessment for members of the three ethnic groups, with highest rates for EA students, lowest for Asian individuals, and an intermediate rate for Hispanic students. While not shown in the figures,weed growing system over the 55 weeks 43.0% had at least 1 ARB, including 13.3% with 1, 8.8% with 2, 2.5% each with 4, 5, or 6 ARBs, and 0 to 1.0% each with between 7 and a maximum of 36 ARBs.
As demonstrated by the absence of a significant ethnicity by time interaction in Table 4, general patterns of ups and downs in numbers of ARBs over 55-weeks were similar for the three groups where ARB values tended to diminish between January and March , increase in June in concert with a campus festival known for heavy drinking, decrease again over the summer when most students returned home , and rose after returning to school . However, regarding Figure 1, as shown in Table 3 the ANOVAs carried out at each time point revealed significant differences in the average number of ARBs across groups at every evaluation. After controlling for maximum drinks reported at each assessment and education group assignment, residual statistics for ethnic group differences in ARBs at each time point across EA, Hispanic, and Asian subjects remained significant at Times 2 and 4. The absence of a main effect for ethnicity in the mixed-design ANOVA in Table 4 indicates the possibility that other characteristics may have impacted results. Therefore, Figure 2 presents ARB trajectories for the three ethnic groups for female and male students separately. While not shown, during the 55 weeks, 48.0% of females and 34.7% of males reported at least one ARB, with an average of 0.30 and 0.19 ARBs per assessment, respectively. Ethnic group differences in ARBs were prominent among females, with the highest ARB rates for EA women, the lowest for Asian individuals, and intermediate, but relatively low, rates for Hispanics. Looking at each assessment for females, statistical analyses in Table 3 demonstrate significant ethnic differences in the rates of ARBs for raw ARB numbers at every assessment, which remained significant at times 4, 5 and 8 after controlling for education group and maximum drinks. Differences across ethnic groups were less apparent for males, and the ethnicity by sex by time interaction was significant in Table 4.
Also, for between subjects’ analyses where time was collapsed and average scores across the eight time points were used, there was a significant sex main effect, and the ethnicity by sex interaction was a trend . Next, the potential relationship of LR to the ethnic patterns of ARBs over time was evaluated in Figure 3. Here, high and low LR subjects showed the same general pattern of ARBs across time demonstrated in Figure 1, including highest rates of ARBs per assessment for EA, lowest for Asian, and intermediate rates for Hispanic students. However, ethnic group differences in ARBs were more robust for high LR subjects, with Table 3 revealing significant differences in raw ARB numbers across the three ethnic groups at every assessment, which remained significant at Time 7 after controlling for maximum drinks and education group assignment, with a trend at Time 4 . The only significant differences in raw ARB numbers for low LR subjects were noted at Time 2 and 4, each of which lost significance once residuals were used. In Table 4 the sex by LR by time interaction was significant and the LR group by time interaction for patterns of ARBs was a trend . Thus, the relationship of LR to differences in ARB patterns across ethnic groups was modest, and was most robust when considered in the context of sex effects. Regarding Hypothesis 4, as briefly alluded to above, the overall analysis in Table 4 indicates interactions regarding ARBs among ethnicity, sex, and LR in two 3-way interactions . However, the 4-way interaction was not significant. It is important to note that cross-sectional data in Figures 1 to 3 were analyzed after controlling for the education group in which students participated. Table 4 offers additional information about effects of educational group assignment, which was used as a covariate. Here, the education group by time interaction was a trend , and the education group main effect was significant, with controls having higher ARB frequencies than the active education participants.
Alcohol-related blackouts are highly prevalent phenomena associated with potentially severe problems . Recently, the prevalence of ARBs has reached alarming rates, especially in females and individuals with early onset drinking . The UCSD freshmen studied here are no exception to these trends as 43% of these students reported at least 1 ARB during the 55 weeks, including 48% in females and 35% in males. While the risk for these alcohol-related anterograde memory lapses increases with BACs , ARB vulnerabilities were also related to ethnic background, female sex, and levels of response to alcohol. The patterns and interactions among these characteristics are the focus of this paper.The current analyses added potentially useful data to the study of ARBs. The sample is relatively large, and subjects were assessed prospectively eight times over 55 weeks during a life-period likely to involve heavy drinking . Several assessments were scheduled at periods when the rates of ARBs were likely to change, including following a heavy drinking campus festival, summer break, and after returning to school as sophomores . Data were evaluated while controlling for maximum drinks, thus diminishing the possibility that ARB patterns simply reflected impacts of heavy drinking itself, and after controlling for possible effects of the prevention trial from which the data were extracted. The major questions focused on improving understanding of how ethnicity, sex,indoor farming systems and LR related to rates of ARBs. To address Hypothesis 1, evaluations began with documentation of expected ethnic group differences in rates of ARBs across time. Consistent with most prior studies, the highest rates were observed for students of EA origin, the lowest among Asian students, with an intermediate rate for Hispanic individuals. This pattern of the number of ARBs persisted after controlling for maximum drinks and the prevention group in which a person participated in the larger study. While fluctuations in ARBs across the year were fairly similar for the three ethnic groups , rates of ARBs were different across ethnicities. As suggested by several recent papers and predicted in the first part of Hypothesis 2, women had higher ARB rates. However, contrary to the second half of that hypothesis, the relationship of ethnicities to ARBs over time was different in females and males. The expected pattern of highest ARBs in EA students and lowest in Asian individuals was most obvious for females and less prominent for males. The mixed-design ANOVA in Table 4 demonstrated significant sex main effects, as well as ethnicity by sex by time and sex by LR by time interactions. The key role of sex in the rates of ARBs over 55 weeks and the interactions of sex with ethnicity might reflect several mechanisms. First, women develop higher BACs per drink , which may translate into higher risks for ARBs. The differences across ethnicities may be especially strong in women vs. men as Asian and Hispanic women may also have stronger culture-based prohibitions against heavier drinking than seen in EA cultures . Also, while more research is needed, considering recent documentation of potentially genetically-related physiologic characteristics that may relate to the BAC required for ARBs , higher rates of ARBs in EA women might reflect some sex-related biological mechanisms that contribute directly to the ARB risk. The first part of Hypothesis 3 was also supported in that a low LR was related to higher ARB rates in these subjects. However, the data in Figure 3 indicate that the relationships of ethnicity to ARBs differ in high- and low-LR subjects.
It is possible that greater differential in ethnicity-related ARB risks might be observed primarily in subjects with higher LRs where drinking quantities are not already elevated by a low sensitivity to alcohol.Finally regarding hypotheses, the prediction that the ethnic group status will interact with sex and LR to predict ARB propensity was partially supported. Table 4 demonstrates significant 3-way interactions for ethnicity by sex by time and sex by LR by time, but the overall 4-way interaction was not significant . Still, the findings underscore the contention that there is more to ARBs than just how much a person drinks, and support the prediction that ethnicity, sex and LR all relate to ARB patterns. The optimal understanding of how ARBs develop requires considering a range of characteristics, preferably in a prospective study . The complex relationships with which multiple factors relate to ARB risks may indicate opportunities for more focused and efficient prevention by identifying subgroups most likely to experience ARBs and who are most likely to gain from programs aimed at decreasing heavy drinking. The larger study from which these data were extracted and a smaller investigation at another university indicated that active education about alcohol-related risk factors are associated with less intense future drinking. In the current study, the significant active education group vs. control group main effect in Table 4 supports the conclusion that decreases in maximum drinks seen with participation in the educational videos were also associated with lower levels of ARBs over time . Thus, universities and other institutions interested in decreasing the risk for ARBs and associated problems might consider developing similar education programs and focusing their efforts on subgroups of subjects with the highest ARB risk. As is true for all research, it is important to recognize caveats regarding the current work. The data were extracted from a larger study evaluating different ways of decreasing heavy drinking among students, and consistent with a prior report focusing on heavy drinking , exposure to active intervention affected ARB rates, a factor that complicates interpretation of results. However, as shown in Table 4, the current results remained robust when prevention group assignment was used as a covariate in the mixed design ANOVA. The relationships among ethnicity, LR and changes in drinking over time are the focus of several other papers and, due to space constraints, are not discussed in detail here . Also regarding the larger study, the subjects were from a single California university, and the generalizability of results to other settings needs to be established, including gathering data on additional ethnic minorities as our analyses were limited to EA, Hispanic and Asian individuals. Next, the data were gathered on-line rather than in person by research staff with whom students had no personal contact, a step that might have affected the veracity of the responses, but the level of impact or direction of effect cannot be determined. Also regarding the larger study from which these data were extracted, to maximize the number of students receiving educational videos only 13% of the subjects were controls, and differences in numbers of subjects across groups may have impacted on current results.