The 2019 novel coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused devastating effects worldwide. There is still no complete understanding of the factors predisposing to COVID-19, which may help identify the vulnerable population and design effective therapies and lifestyle changes to combat it.
Study: Factors influencing COVID-19 Infection in older individuals: History of Alcohol Use Disorder, Major Depressive illness, genetic variation and current use of alcohol. Image Credit: Alina Troeva/Shutterstock
The present study released as a preprint in the medRxiv* server attempts to identify the factors that increase the risk of COVID-19 infection or confer protection against COVID-19 in a study population above 55 years of age known to experience higher morbidity and risk of mortality from COVID-19.
How was the study performed?
The present study was conducted on individuals who had previously participated in a family study conducted on families with family members suffering from multiple cases of alcohol use disorder (AUD) or the control families who did not have anyone with AUD. The subjects from the proband generation or their parents were included, and the age of the study population ranged between 55 and 103 years at follow-up. Extensive clinical data was collected from them at two points of time, one at middle age and the other at old age.
The study was conducted as interviews. Both first and the second follow-up interviews attempted to collect clinical data such as the history of alcohol or drug use, psychiatric conditions diagnosed, and history of health conditions. The second interview additionally collected data on the history of exposure to SARS-CoV-2. The interviews were conducted on 90 subjects, and the majority of them belonged to a higher socioeconomic status and were females. The span of the longitudinal study was 32 years.
The present study found a significant correlation between the quantity of liquor consumed and the presence or absence of covid-19. This finding is similar to previous reports, which showed that there was enhanced immune functioning in individuals who consumed low levels of alcohol of up to one drink per day. The effect was not present in the case of beer or wine. This can be explained by the fact that liquor consumption leads to a faster rise in alcohol levels in the blood, unlike beer or wine, where larger quantities should be consumed.
Diagnostic and Statistical Manual of Mental Disorders III (DSM-III) criteria or Feighner criteria were used to diagnose alcohol use disorder. It was found that the previous diagnosis of AUD was not associated with COVID-19, and during the follow-up interview, Feighner criteria for alcohol use disorder was also not associated with COVID-19.
In the follow-up interview, the participants were asked a single question about whether they were presently depressed or if they were depressed in the past. No significant association was drawn between the presence or absence of COVID-19 and the response to this question.
However, a significant correlation was identified between the lifetime occurrence of depressive disorders and COVID-19 incidence. The information on the incidence of depressive episodes was gathered from questions in the interview concerning the occurrence of low moods that extend for two weeks or more associated with neurovegetative symptoms such as loss of appetite.
A significant association was observed between patterns of depressive episodes reported at the two-time points and the occurrence of COVID-19. Participants who did not report episodes of depressive disorder are less likely to contract COVID-19 infection. A large proportion of participants who reported the occurrence of depressive episodes in the follow-up interview had COVID-19 irrespective of whether they reported an episode or not during baseline. There was less occurrence of COVID-19 in participants who reported an episode at baseline and an absence of episode during follow-up.
In the study population, 63.7% of participants in the group reported past or current incidence of hypertension in the COVID-19 negative group (COVID-19 -ve), and 50% reported past or current incidence of hypertension in the COVID-19 positive group (COVID-19 +ve). The present study did not find a statistically significant correlation between the presence or absence of hypertension and the reported occurrence of COVID-19 amongst the study participants. The lack of association observed may be due to the control of hypertension in the study population through antihypertensives.
The incidence of COVID-19 in participants with hypertension using ACE inhibitors was additionally investigated. 18.9% of participants were using ACE inhibitors, and when the COVID-19 +ve and COVID-19 -ve groups were compared, there was no significant difference in the incidence of COVID-19 between the groups.
The study also attempted to explore an association between human leukocyte antigen (HLA) and red blood cell type and the incidence of COVID-19. Class 1 HLA variants were analyzed, including A1, A2, A3, B8, B44, and BW5. A significant association was observed only in the case of males for A1 and B8. Amongst males, 80% of COVID-19 +ve participants carried A1, and 80% of the COVID-19 positive group carried B8.
In the case of red blood cell antigens, it was found that individuals who were homozygous for the non-dominant alleles of Kidd red cell antigens are protected from developing COVID-19. Other red cell antigens such as ABO, Duffy, Kell, and Rh did not significantly correlate with COVID-19 status.
The current study presents new information on the association between the presence or absence of COVID-19 and factors such as pre-existing mental and physical health issues, current use of alcohol, and blood markers in individuals above 55 years of age who were residing in their homes.
The study found that low levels of alcohol consumption in the form of liquor results in reduced incidence of COVID-19, history of AUD do not increase the risk of COVID-19, mood disorders increased the risk of COVID-19, HLA variants A1 and B8, and the Kidd red cell antigens were significantly associated with COVID-19 status.
The findings from this study may help in healthcare decisions to protect vulnerable older adults from COVID-19 infections and to design treatment strategies. Further, investigations with a larger population are required to confirm the findings from this study.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.