The 839 individuals who completed the study came from 43 states, including Alaska and the District of Columbia. Of these, 548 were female and 291 were male. Age ranged from 18 to 75 with the mean – SD of 45.5 + 13.1 years. There was no statistical difference in age between females and males . The percent of individuals versus the length of their CBD use is shown in Figure 1. Table 1 shows the number and percent of individuals taking the various compositions of CBD and compares the average daily doses. Full-spectrum hemp oil was taken by 55.7%, CBD-isolate by 40.5%, and broad spectrum CBD by 3.8%. Overall, the mean – SD daily dose of CBD was 50.3 + 40.7 mg/day. Full spectrum users’ daily dose was 40.0 + 36.8 mg, CBDisolate users , and broad-spectrum users . The upper limit of the range for each group is several times that of the mean. The forms by which the different compositions of CBD were taken are listed in Table 2. Almost half of the participants used a tincture, whereas 22.1% used a capsule or pill, 13.9 used an edible formulation, 12.6% used a nanotechnology-treated product, and 1.7% used an additive that could be added to a slushy or food. The average daily dose of the nanotechnology-treated CBD was significantly lower than any of the other forms of CBD used. This nanotechnology-treated CBD was a full-spectrum product. When it was removed from the analysis,vertical aeroponic farming the average daily dose of full-spectrum CBD increased to 63.2 + 41.8 mg. There was no statistical difference in average dosage between the different compositions or forms of CBD used when the nanotechnology-treated CBD was excluded from the analysis. Table 3 shows the prevalence of the LT in this study. The number and percentage of individuals with elevated LT were: ALT 9.1%, AST 4.0%, ALP 1.8%, and TB 1.4%.
The prevalences of elevated ALT and AST were significantly higher than the 2.5% prevalence in a normal population with no medical conditions . However, they were not significantly different from their reported prevalences in the general adult U.S. population .6 The prevalence of TB was significantly less that the normal population prevalence of 2.5% , and the prevalence of ALP was not different than the normal population prevalence of 2.5%. The prevalence of those having either an elevated ALT or AST was 10.2% , which was not statistically different than the reported prevalence in the general adult U.S. population .Although BMI, age, and gender were highly correlated with ALT percentile level, multiple regression adjustment found that only BMI and age had an effect on predicting elevated ALT percentile levels. As is illustrated in Figure 2, there was no statistical correlation between the percentile level of ALT and the daily dose of CBD. In addition, there was no significant correlation with any of the other values, including length of use and percentile ALT level. The mean value for daily dose of individuals with elevated AST was 52.3 + 41.0 mg/day and 50.1 + 36.3 for those with normal AST. There was no significant difference in the prevalence of elevated LT between companies , nor was there any difference between CBD compositions . There were, however, significant correlations between ALT levels and AST and ALP levels but not with TB. All the LT values were reasonably approximated by a normal distribution, but the ALT distribution had an extended right tail, which corresponds to the increased incidence of elevated ALT levels as compared with a normal, healthy population. It should be noted that one individual had an LT drawn at week 2 of the study for reasons that are unknown and reported that their LTs were abnormally high. However, he continued in the study and at week 4 when his LTs were drawn for this study, his LTs had returned to normal. The number of individuals with medical conditions was 585 of the total subjects and the average number of medical conditions per person was 2.7 + 2.34. The number of subjects with medical conditions with normal ALT values was 539 with a mean of 2.7 + 2.3, while those with elevated ALT values was 46 and 2.8 + 2.72, respectively. Similarly, the number and percentage of subjects taking prescription drugs was 525 overall, 476 for individuals with normal ALT levels,and 49 for those with elevated ALT levels. Overall, an average of 2.4 + 2.3 drugs per person was taken, while those with normal ALT levels took 2.4 + 2.3 drugs and those with elevated ALT levels took 2.3 + 1.8 drugs.
There were no significant differences between any of these values. Of the 76 individuals with elevated LTs, 33 agreed to have follow-up LTs performed by our laboratories or by their local physician . The remaining 43 individuals either refused to agree to have a follow-up LT or never showed up at the laboratory for the test. Of the individuals having follow-up LT data, one individual had an ALT 3 · ULN, an elevated AST, and normal ALP and bilirubin levels on the first set of LT, stopped CBD for 4 months and continues to have essentially the same levels of LT. Two individuals had an initial ALT > 2 · ULN and < 3 · ULN and both had normal LT on follow-up. One continued on CBD and the other, who was also consuming large amounts of alcohol throughout the study, stopped taking CBD and reduced her alcohol intake. All the remaining individuals had initial ALT levels > 1 · ULN and < 2 · ULN and none of these individuals had stopped CBD because of their ALT levels. Of these, seven continued to have an elevated ALT > 1 · ULN and < 2 · ULN. One individual’s ALT increased to > 2 · ULN and < 3 · ULN. This individual had an elevated LT before starting the study due to acetaminophen toxicity and restarted the acetaminophen between the first and the second LT.Three other individuals also admitted to having had elevated LT in the past, but claimed they had not indicated such when being screened for the study because they knew it would exclude them from participating. Three individuals’ repeat ALT increased to > 3 · ULN, two of whom started consuming marijuana products between the two tests and the other had a third set of LT which was normal even though she was continuing on her CBD. This last individual was taking three drugs , which are known to be associated with elevated LTs. There was no relationship between continuing to take CBD, daily dose of CBD and ALT levels or change in ALT elevation severity. There were no differences in any of the initial data in the severity of LT elevation between those that had follow-up LT performed and those that did not. Therefore, ultimately 30 of the 33 individuals had their ALT levels ultimately return to normal or remain minimally elevated . The three individuals with significantly elevated ALT had reasons to explain their continued elevation that were not related to CBD consumption,vertical cannabis farming as described above. Of the 1475 individuals enrolled in the study, 33 reported an adverse reaction, of which 31 were classified as unrelated to CBD ingestion with two being classified as possibly related. These two consisted of one case of atrial fibrillation and one case of constipation and psychoactive effects.Although it would have been ideal to have a controlled, double-blinded clinical trial to study this issue, at the time of design and beginning performance of this study, CBD was considered a class 5 drug in the United States. Therefore, even though CBD use was widespread, such a trial was difficult, if not impossible to perform using commercial CBD. Therefore, this observational study was thus performed in its stead.
The ALT data in this population study are similar to other population studies, which found that the level of ALT is affected by BMI, age, and gender. These studies also found significant correlations among ALT, AST, and ALP levels, which also were found in this study. These similarities suggest that the sample in this study is representative of the general adult population. In this self-selected sample of individuals who were self-dosing CBD, there was an increased prevalence of LT elevation as compared with a normal healthy population with no medical conditions. However, individuals in this study were taking CBD primarily for medical reasons, making laboratory comparisons of this population to that of a normal healthy population unrealistic, as a large proportion of the individuals with medical conditions in the United States will have abnormal values.10 When compared with the general adult population norms in the United States, the prevalence of elevated ALT and/or AST was no different. Although comparing the prevalence of elevated ALT to the general population seems illogical when the exclusion criteria for this study included ‘‘having a history of elevated LT,’’ such a comparison was made because several individuals knowingly falsified their history of elevated LT so that they could be included in the study. The transient nature of elevated LT in most individuals in this study is similar to that seen and reported in the general population and, in the majority, their LT reverted to normal even though CBD ingestion was continued.6,7 In the few individuals with persistent severely elevated or worsening severity of ALT elevations, the cause can easily be attributed to factors other than CBD. In this study, the vast majority of participants with elevated ALT and/or AST had levels < 2 · UNL and among the few individuals with levels > 2 · UNL, none had any elevation of ALP or TB. Even though a number of individuals consumed large amount of CBD, there was no increase in prevalence of elevated AST levels. In fact, the daily mean dose and standard deviation were essentially the same in both those with normal and elevated AST levels. CBD was not found to be a factor in determining ALT levels, not a single individual in this study had liver disease, and the prevalences of ALP and TB in this population of CBD users were lower than those found in the normal healthy population. This suggests that self-medication of CBD in some individuals may help prevent liver disease, as has been suggested in animal and in vitro studies.This paradoxical in effect on drug-induced liver damage with difference in dosing levels of CBD is not new.Many of the individuals in this study had been taking multiple drugs, including many that are known to cause LT elevations, and this fact has been a common theme in CBD-associated LT elevations in most studies when this association has been examined. However in these studies, the daily dose was a significant factor in the association. In this study, the average daily dose was 0.65 – 0.57 mg/kg/day, which is an order of magnitude less and was comparable to other studies that examined the daily dose typically consumed by a self-dosing CBD user. Although, it may be possible that CBD at lower doses can cause transient elevations in LT, the findings of this study support that they are more likely due to demographic, physical, and medical conditions already suffered by the individuals for which they are self-medicating with CBD for relief of associated symptoms. In addition, only 0.14% individuals had an adverse reaction that was considered to possibly have any causal relationship to taking CBD.Traumatic brain injury is a significant public health concern as it is a leading cause of mortality, morbidity and disability in the United States . According to the World Health Organization, TBI is expected to become the third leading cause of death and disability in the world by 2020. In the United States TBI contributes to a third of all injury related deaths . A traumatic brain injury, as defined by the Centers for Disease Control and Prevention , is a disturbance of the brain’s normal function that occurs when an individual sustains a blow, jolt, or bump to the head, or sustains a penetrating head injury .