Under-Estimation of Alcohol Consumption among Women At-Risk for Drinking during Pregnancy
Witbrodt, Jane, Kaskutas, Lee Ann, Korcha, Rachael, Armstrong, Mary Anne, Contemporary Drug Problems
This study adds to a growing literature showing that definitions for "standard drinks" are often difficult to conceptualize and that people often underestimate their actual drink sizes. As part of an intervention aimed at reducing negative neonatal and maternal outcomes, insured at-risk women were asked to identify the vessels from which they drank each of six beverages (n=266). We calculated differences between their actual and standard drink sizes. Additionally, differences were compared to those reported in an earlier study of uninsured inner city minority women that used identical vessels methodology. Over half of the spirits, fortified wine and malt liquor drinkers underestimated the actual number of ounces their drinks contained. Most spirits drinkers (90%) and approximately three-quarters of the wine and malt liquor drinkers drank larger-than-standard drink sizes, with the median drink size 1.5 to 2.0 times larger than the standard size for those beverages. Heavier drinkers (≥3 drinks per sitting) were more likely than lighter drinkers to underestimate their drink sizes. Findings were similar to those in the previous study using identical drink size measurements. Accurately assessing true drink sizes is underscored when the social, health and epidemiologic consequences associated with miscalculation are considered.
KEY WORDS: Drink size, drink volume
Over recent years, researchers have heeded the call for improved measures of alcohol consumption and have begun to develop more sophisticated methodologies to assess actual use for both general populations (Dawson, 2003; Kerr, Greenfield, Tujague & Brown, 2005; Martin & Nirenberg, 1991; Midanik, 1982; Miller, Heather & Hall, 1991; Williams, Proudfit, Quinn & Campbell, 1994; Wilson, 1981) and specialized populations, such as pregnant and parenting women (Ernhart, Morrow-Tlucak, Sokol & Martier, 1988; Russell, Chan & Mudar, 1997). For example, an earlier study with uninsured pregnant urban women found that when drink size was considered, average daily volume during pregnancy increased to the risk level for fetal alcohol syndrome (Kaskutas, 2000). This article offers further evidence that drink size should be an important element in assessing potential risk. We focus specifically on an insured population of childbearing-aged females identified as at-risk for drinking during pregnancy by their prenatal care provider.
Historically, a common practice in national survey research (and a practice often used in smaller clinical studies) has been to instruct respondents to report the quantity and frequency of their alcohol intake over some reference period (Greenfield, 2000; Room, 1990). Alcohol use questions are usually prefaced with a definition of a "standard drink;" for example, "a 12-ounce can of beer, a 4-ounce glass of wine or a 1 -ounce shot of liquor" (Alcohol Research Group, 1964-2005; Greenfield, Midanik & Rogers, 2000; Stockwell, Donath, Cooper-Stanbury, Chikritzhs, Catalano & Mateo, 2004), or "a can or bottle of beer, a glass of wine or a wine cooler, a shot of liquor, or a mixed drink with liquor in it" (Office of Applied Studies, 2005). In this case, respondents are required to make quick mental translations to estimate the actual number of "standard drinks" they drink based on the size and alcoholconcentration across all beverages consumed. Other surveys ask respondents to report the number of ounces in their typical drinks for specific beverages (National Institute on Alcohol Abuse and Alcoholism, 2004). Both methods assume that respondents can conceptualize how much a fluid ounce is, an assumption challenged by a growing number of studies showing otherwise (Graves, Kaskutas & Korcha, 1999; Stockwell, et al., 2004; Wansink & van Ittersum, 2005; White, Kraus, Flom, Kestenbaum, Mitchell, Shah, et al., 2005).
To achieve more accurate consumption estimates, researchers have responded in innovative ways, for example, by asking respondents to designate their usual pour level for drinking vessels depicted in life-size photographs (National Institute on Alcohol Abuse and Alcoholism, 2004); or from a selection of actual glasses, bottles, and cans augmented by an array of vessel photographs (Kaskutas & Graves, 2000; Russell, Marshall, Trevisan, Freudenheim, Chan, Markovic, et al. …