You'll have to absorb this on your own since your doctor will likely reflexively tell you no alcohol.
Alcohol Consumption and Incident Stroke Among Older Adults
The Journals of Gerontology: Series B, Volume 73, Issue 4, 16 April 2018, Pages 636–648, https://doi.org/10.1093/geronb/gbw153
Published:
10 February 2017
Article history
Abstract
Objectives
This
study examines the relationship between alcohol consumption and
incident stroke among older adults and tests whether alcohol consumption
contributes to observed race and sex differences in stroke.
Method
Data
are from a U.S. national cohort of black and white adults aged 45 and
older, the REasons for Geographic And Racial Differences in Stroke
(REGARDS) study. Current and past drinking levels were reported at
baseline (2003–2007). Participants who had never had a stroke were
followed for adjudicated stroke events through September 2015 (n
= 27,265). We calculated Cox proportional hazard models for stroke,
adjusting for demographic, socioeconomic, behavioral, and health
characteristics.
Results
Participants,
mean age 64.7 years, consumed on average 2.2 drinks/week and
experienced 1,140 first-time stroke events over median 9.1 years
follow-up. Nondrinkers had a 12% higher risk of stroke than current
drinkers; the risk of stroke among nondrinkers largely reflected high
risks among past drinkers; these differences were explained by
socioeconomic characteristics. Among current drinkers, light drinkers
had significantly lower stroke risks than moderate drinkers after
accounting for demographic, socioeconomic, behavioral, and health
characteristics. Implications of alcohol did not differ between blacks
and whites but did differ by sex: Especially among women, nondrinkers,
and specifically past drinkers, had higher risks; these differences were
largely explained by health characteristics and behaviors. Alcohol did
not explain race and sex differences in stroke incidence.
Discussion
Among
older adults, those who used to, but no longer, drink had higher risks
of stroke, especially among women; current light drinkers had the lowest
risk of stroke.
Issue Section:
Articles
Few studies have examined the health implications of alcohol consumption for older adults, but there is some evidence that moderate alcohol consumption is also linked with lower mortality at older ages (Goldberg, Burchfiel, Reed, Wergowske, & Chiu, 1994; Thun et al., 1997). For adults, especially at older ages, stroke is a major cause of morbidity and mortality (Howard & Goff, 2012; Mozaffarian et al., 2015). This study examines the relationships between alcohol consumption among older adults and their risk of stroke.
Alcohol Consumption Patterns
In the United States in 2012, 71% of adults aged 18 years and older reported drinking in the past year, and 51.3% of adults were current regular drinkers, defined as 12 or more drinks in the past year (Schiller, Lucas, Ward, & Peregoy, 2012). Older adults tend to decrease their total alcohol intake after retirement (Ferreira & Weems, 2008); in a 2008 national survey, approximately 40% of adults aged 65 years and older reported that they drank alcohol (Jardim-Botelho et al., 2014).Alcohol consumption patterns differ by sex and race (Petrea et al., 2009; Rosamond et al., 1999). Men tend to drink more frequently and in larger amounts than women, and women are more often lifetime abstainers (Wilsnack, Vogeltanz, Wilsnack, & Harris, 2000); these patterns are similar for adults aged 65 years and older (Ferreira & Weems, 2008). Whites are more likely to drink alcohol, but blacks who drink have higher volume of intake and frequency of heavy drinking (Chartier & Caetano, 2010; Fesahazion, Thorpe, Bell, & LaVeist, 2012; Kerr, Patterson, & Greenfield, 2009). Fewer black than white men are heavy drinkers; however, those black men who are heavy drinkers tend to maintain heavy drinking practices to older ages (Chartier & Caetano, 2010).
Alcohol Consumption and Health
Several studies have shown links between alcohol consumption, morbidity, and mortality. Even after controlling for numerous possible confounders, such as age, employment, race, smoking, blood pressure, body mass index (BMI), fat consumption, and cholesterol, the relationship between alcohol consumption and mortality is U shaped (Fuller, 2011; Liao, McGee, Cao, & Cooper, 2000; Marmot et al., 1981; Paganini-Hill, Kawas, & Corrada, 2007; Thun et al., 1997; Wannamethee & Shaper, 1997). Studies have found U-shaped relationships between alcohol consumption and cardiovascular disease (CVD) mortality in several populations (Fuller, 2011; Marmot, 1984; Thun et al., 1997). Data from the Cancer Prevention II study of adults aged 30 years and older showed that risk of death from coronary heart disease and other circulatory diseases was lower for men and women who drank one to three drinks per day compared with those who did not drink (Thun et al., 1997). Nationally representative U.S. data indicated that moderate drinkers had lower all-cause and coronary heart disease mortality than nondrinkers, even when adjusting for age, race, education, marital status, employment, smoking, income, self-reported health, and previous diagnosis of heart problems (Fuller, 2011). In the Whitehall Study of male civil servants aged 40–64 years in England, CVD mortality was higher among nondrinkers than among drinkers (Marmot et al., 1981).Biological mechanisms could underlie cardioprotective effects of moderate drinking. Specifically, moderate drinking increases levels of high-density lipoprotein cholesterol, which can prevent clots and reduce platelet aggregation and so can protect against CVD and stroke (Agarwal, 2002).
At the same time, inverse associations between alcohol intake and morbidity and mortality could be spurious (Fillmore, Stockwell, Chikritzhs, Bostrom, & Kerr, 2007; Thun et al., 1997). For example, in the United States, nondrinkers often are from poorer socioeconomic circumstances and have lower levels of education than drinkers, and socioeconomic status and education are positively associated with health; thus, the poorer health outcomes of nondrinkers may be due to their socioeconomic disadvantage rather than their avoidance of alcohol (Fekjaer, 2013; Fillmore et al., 2007; Naimi et al., 2005; Naimi, Xuan, Brown, & Saitz, 2013). Therefore, it is important to examine associations using adequate controls for socioeconomic status and to not rely on cross-sectional associations. Another concern is that people may stop drinking precisely because they are experiencing health problems, entailing possible reverse causation. Thus, former drinkers may be at higher risk for adverse health outcomes; occasional drinkers (less than 12 drinks/year) may also include individuals who reduced their alcohol intake due to health problems. Therefore, former drinkers, occasional drinkers, and lifetime abstainers should be separated in analyses, as combining them may show artificially high risks for nondrinkers. Some of the documented protective effects of alcohol may disappear when former drinkers and occasional drinkers are separated from lifetime abstainers (Fillmore et al., 2007). In addition, consequences may differ for those drinking seven drinks over the course of a week or over the course of one day, so patterns of drinking should be considered (Marmot, 2001; Thun et al., 1997). Nonetheless, several studies showed that moderate alcohol consumption was associated with better outcomes, even after controlling for socioeconomic status and distinguishing former and occasional drinkers from lifetime abstainers. They have shown a U-shaped relationship between alcohol consumption and all-cause mortality, coronary heart disease mortality, and intracerebral hemorrhage (Thrift, Donnan, & McNeil, 1999).
Patterns of Stroke and Associatons With Alcohol
There are two major types of stroke: (a) ischemic stroke accounts for the majority of strokes in the United States and occurs as a result of an obstruction in a blood vessel supplying blood to the brain; (b) hemorrhagic stroke occurs when a weakened blood vessel ruptures. The association between alcohol consumption and stroke may vary with type of stroke (Klatsky, 2015).Across case–control and cohort studies, ischemic stroke morbidity and mortality had J-shaped relationships with alcohol consumption (Camargo, 1996; Patra et al., 2010). A meta-analysis of 35 studies found lower risks of stroke for drinkers who consumed ≤12 g of alcohol per day compared with abstainers (Reynolds et al., 2003): light drinkers had a 17% lower risk of total stroke and 20% lower risk of ischemic stroke compared with abstainers; moderate drinkers (12–23 g/day) also had a 25% lower risk of ischemic stroke compared with abstainers.
Hemorrhagic stroke morbidity and mortality increased with alcohol use (Camargo, 1996; Patra et al., 2010), with a positive linear relationship between alcohol consumption and hemorrhagic stroke (Reynolds et al., 2003). Although heavy drinking is associated with hemorrhagic stroke, the relationships between light-to-moderate alcohol consumption and hemorrhagic stroke have been conflicting, likely because of small numbers of hemorrhagic strokes in most studies (Owolabi & Agunloye, 2013; Patra et al., 2010; Thrift et al., 1999).
Another meta-analysis of 27 prospective studies found that light drinkers had a lower risk of total stroke, ischemic stroke, and stroke mortality but not hemorrhagic stroke; heavy drinkers had higher risk of total stroke but not of hemorrhagic stroke, ischemic stroke, or stroke mortality (Zhang et al., 2014). In the ARIC study of older adults across four U.S. communities, light and moderate drinkers did not have a lower incidence of ischemic stroke than abstainers, whereas heavy drinkers had higher incidence (Jones et al., 2015).
In a prospective cohort of Swedish older adults, those who had been very light drinkers (<0.5 drink/day) in middle age had significantly lower risks of stroke during the following four decades than did heavy drinkers (>2 drinks/day) and nondrinkers; the risk of stroke among nondrinkers increased with age, whereas the risks associated with heavy drinking decreased (Kadlecová, Andel, Mikulík, Handing, & Pedersen, 2015).
Stroke incidence and mortality differ between blacks and whites in the United States (Gillum, 1999; Go et al., 2014; Howard et al., 2011; Kleindorfer et al., 2010; Sacco et al., 1998): black men have the highest age-adjusted rate of incident stroke (4.4/1,000 person-years), black women the second highest (3.1/1,000 person-years), and white men (1.8/1,000 person-years) and women the lowest (1.2/1,000 person-years; Rosamond et al., 1999). Stroke mortality rates follow similar patterns (Gillum, 1999).
Whether the relationship between alcohol consumption and stroke outcomes differs for men and women remains uncertain. Some studies have reported lower risks of incident stroke among drinkers for both men and women, but different patterns with respect to stroke mortality (Ikehara et al., 2008; Zheng et al., 2015). Others have reported protective effects only for women (Hansagi, Romelsjo, Gerhardsson de Verdier, Andreasson, & Leifman, 1995); still others have reported that women experience a J-shaped relationship rather than linear relationship for hemorrhagic stroke (Jimenez et al., 2012).
This study examined the relationships between alcohol consumption among older adults and their risk of experiencing a stroke. As previous research identified higher risk of stroke among blacks compared with whites and among men compared with women, as well as differences in alcohol consumption patterns across these groups (Fesahazion et al., 2012; Go et al., 2014; Howard et al., 2011; Kleindorfer et al., 2010; Petrea et al., 2009; Sacco et al., 1998), we explore whether differences in alcohol consumption explain some of the observed differences in stroke risks between blacks and whites and between men and women.
Method
Data
We used data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a national longitudinal study of black and white adults aged 45 years and older (n = 30,239). Stroke risks differ across regions of the United States (Borhani, 1965; Howard et al., 2011), and the REGARDS study was designed to measure and understand these differences (Howard et al., 2005). Therefore, a stratified random sample was conducted with oversampling in the region dubbed the “stroke belt” (Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee; Lanska & Kuller, 1995). Twenty-one percent of the sample was randomly selected from the “buckle” of the stroke belt (coastal plain region of North Carolina, South Carolina, and Georgia), 35% from the rest of the stroke belt states (remainder of North Carolina, South Carolina, and Georgia plus Alabama, Mississippi, Tennessee, Arkansas, and Louisiana), and the remaining 44% from the other 40 contiguous U.S. states. Blacks were oversampled to characterize racial differences in stroke.Participants were recruited between January 2003 and October 2007. Each participant was first mailed a letter and brochure explaining the study and then telephoned to recruit and obtain verbal consent. Written consent was obtained during the subsequent in-person evaluation. Using a computer-assisted telephone interview (CATI), trained interviewers obtained information on demographic and socioeconomic characteristics, medical history, and lifestyle risk factors. A brief physical exam, including blood pressure measurements, blood samples, and anthropometry, was conducted in-person 3–4 weeks after the CATI. Participants were contacted every 6 months by telephone to document self- or proxy-reported suspected stroke. The institutional review boards of participating institutions approved the study. Additional details on REGARDS are provided elsewhere (Howard et al., 2005).
REGARDS cooperation and response rates at baseline were 49% and 33%, respectively, comparable with other cardiovascular cohort studies (Morton, Cahill, & Hartge, 2006). During follow-up, more than 80% of participants completed at least 75% of follow-up. The REGARDS study is still ongoing, but, for this analysis, we used follow-up data through September 2015.
Respondents who had reported having ever experienced a stroke at baseline were excluded from this analysis (n = 1,930), as were those missing in-person data (n = 56), those who only participated in the baseline questionnaire (n = 447), and those who did not respond to questions about alcohol (n = 541), resulting in an analytic sample of 27,265.
Alcohol Determination
Data on alcohol use were collected through questions at baseline. The first was “Do you presently drink alcoholic beverages, including beer, wine, and other drinks made with hard liquor, even occasionally?” If answered affirmatively, the following question was asked: “How many alcoholic beverages do you presently drink? For example, one per day, three per week, and so on. Please include beer, wine and hard liquor.” If participants answered “no” to the first alcohol question, the follow-up question was “Have you ever drunk alcoholic beverages, including beer, wine, and other drinks made with hard liquor on a regular basis? By regular, we mean at least 1 drink per month for 1 year.”We created three measures of alcohol consumption. The simplest was current drinking status: drinker or not drinker. A second measure was drinking history: current drinker, lifetime abstainer, or past regular drinker. The third measure was consumption level, which additionally categorized current drinkers, in line with National Institute on Alcohol Abuse and Alcoholism definitions, as occasional drinkers (current drinkers who did not drink in an average week), light drinkers (up to 1 drinks/week on average for both men and women), moderate drinkers (1–7.5 drinks/week for women and 1–15 drinks/week for men), and heavy drinkers (≥7.5 drinks/week for women and ≥15 drinks/week for men; National Institute on Alcohol Abuse and Alcoholism, 2016).
Stroke Events Determination
The outcome of interest was the occurrence of any adjudicated stroke event in a person who reported never having had a stroke at baseline. During telephone interviews at each follow-up contact, a report of possible stroke, transient ischemic attack, death, hospitalization or emergency department visit for brain aneurysm, brain hemorrhage, stroke symptoms, or unknown reason generated a request for retrieval of medical records. A stroke nurse conducted an initial review to exclude events that were obviously not strokes. Then, medical records of suspected strokes were centrally adjudicated by physicians. For deaths with no medical records, death certificates and/or proxy interviews were used. Stroke was defined using the World Health Organization (WHO) definition of focal neurologic symptoms lasting more than 24 hr or those with neuroimaging data consistent with stroke. Details of this method are described elsewhere (Howard et al., 2011). The outcome variable combined clinical and WHO stroke definitions. Strokes were classified as ischemic or hemorrhagic whenever the type could be determined.Covariates
Self-reported characteristics at baseline were used as covariates in models. Demographic characteristics were: age, race (black, white), and sex (female, male). Social and economic variables were urbanicity of residence (urban, rural, or mixed—county-level category from the 2000 U.S. Census), annual household income (<$20,000, $20,000–$34,000, $35,000–$74,000, >$75,000), education level (less than high school, high school graduate, some college, college graduate and above), and marital status (married, divorced, widowed, single, other). Stroke belt residence is a socioeconomic indicator as well as a sampling criterion (stroke belt, stroke buckle, non-belt). Health and health behaviors measures were smoking (yes, no), physical activity (≥4 times/week, 1–3 times/week, 0 times/week—in response to a question about frequency of engaging in intense physical activity sufficient to work up a sweat), BMI category (underweight, normal, overweight, obese—based on measured height and weight compared with standard CDC cut points), diabetes (yes, no—based on fasting glucose ≥ 126 mg/dL, nonfasting ≥ 200 mg/dL, or self-report of glucose control medication), and hypertension (yes, no—based on systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg, or self-reported current hypertension medication use).Statistical Analysis
The follow-up period for analysis was from recruitment until September 30, 2015. Follow-up time for each participant was calculated from date of in-home visit to date of first stroke, death, or last telephone contact. Similarly, attained age was calculated from date of birth to date of first stroke, death, or last telephone contact. Demographic, social, economic, health, and behavior characteristics at baseline were examined for the entire cohort and then compared across current drinkers and nondrinkers. Continuous variables were summarized as means and standard deviations, and statistical differences were detected using t tests. Categorical variables were summarized as proportions and tested for significant differences using chi-square tests.Cox proportional hazard models were used to estimate the associations between incident stroke and the three measures of alcohol exposure (Table 2), first unadjusted (Model 0) and then sequentially adding demographic characteristics (Model 1), social and economic characteristics (Model 2), and health characteristics and behaviors (Model 3). Attained age was used as the time variable in models.
To determine whether the implications of alcohol consumption were different for blacks compared with whites and for men compared with women, we tested two-way and three-way interaction terms between race and sex and the three measures of alcohol use. Significance of interaction terms was examined using an a priori level of α < .10, which indicates heterogeneity in risk justifying stratified models. Stratified results are presented in Table 3.
As previous research has identified higher risk of stroke among blacks compared with whites and among men compared with women, as well as differences in alcohol consumption patterns across these groups, we examined whether patterns of alcohol consumption explained these differences in risks of stroke (Table 4).
Finally, because the relationships between alcohol and stroke type may differ, we also present stratified models examining relationships between alcohol consumption and ischemic and hemorrhagic stroke (Table 5).
Analyses were conducted using SAS 9.3. The proportional hazards assumption was tested by including the cross-product of log-transformed age and each of the covariates in the final Cox models.
Results
Drinking patterns are shown in Table 1. Nearly half (48.2%) of the participants were not current drinkers; most nondrinkers (63.3%) were lifetime abstainers. Among current drinkers, more than a third were moderate drinkers, 28.6% were light drinkers, 26.5% were occasional drinkers, and less than 8% were heavy drinkers.More at link.
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