attainment, whereas prestige measures are linked to social hierarchy [12].
SES can also be measured at the community and neighborhood levels. Recent studies on SES include investigations of income inequality across cities or countries, as well as neighborhood poverty and access to resources in neighborhoods (see Other Social Determinants in Section 3.4.2 and examples of neighborhood environment in Section 3.5.3). Among developed nations, the United States has the highest income inequality, with the top 0.1% of the population owning nearly the same share of wealth as the bottom 90% [13]. The United States also has poorer health outcomes compared to other industrialized nations as measured by life expectancy, mental illness, obesity, infant mortality, teenage births, homicides, imprisonment, educational attainment, distrust, and social mobility.
The most commonly used measure of income inequality is the Gini coefficient, “formally defined as half of the arithmetic average of the absolute differences between all pairs of incomes within the sample, with the total then being normalized on mean income. If incomes are distributed completely equally, the value of the Gini will be zero. If one person has all the income, representing complete inequality, the Gini will assume a value of 1” [14].
Research on income inequality and health, including the role of violence, strongly supports a causal link [15]. Furthermore, a growing body of literature linking neighborhoods and health has shown that residing in a disadvantaged neighborhood is associated with increased rates of chronic disease [16]. Data suggest that these neighborhoods have fewer resources available to promote healthy behaviors and facilitate good health (further discussed in Section 3.4.2).
While this SES–health relationship has been robust across many health outcomes and at multiple levels, more work is needed to understand the complexity of the components of SES and how they affect health disparities [11]. These components do not always act independently but, instead, are affected by one another. Determining the biological mechanisms linking these social factors to disease outcomes has been a major priority for the field of social epidemiology.
Racial and ethnic minority populations, who have disproportionately lower SES, are especially affected by stressors related to their minority status (i.e., discrimination and racism) that exacerbate health disparities. Disentangling the effects of race and ethnicity from those of SES is extremely difficult due to the complex historical inequities and ongoing social issues. Rigorously designed studies to address this question are needed.
3.4.2 Other Social Determinants
3.4.2.1 Acculturation
In addition to the health disparities that racial and ethnic minority groups experience, the health of immigrant populations is influenced by their level of acculturation. The term acculturation refers to changes in the values, attitudes, and behaviors of an ethnic minority individual due to their continuous interaction with individuals from a different ethnic group. This is one example of an individual mediator and moderator of SES (Figure 3.2). Lower mortality rates for lower acculturated Latinos, despite their relatively low SES—also known as the Latino Paradox—is an example of the relationship between acculturation and health. However, an immigrant's risk of chronic disease and disability has been shown to increase with a greater level of acculturation. Although the reasons for such relationships are complex, there are a variety of measures to assess acculturation level, ranging from a short multiple‐item measure to multidimensional assessments (see Table 3.3).
The biggest advantages of a short multiple‐item measure are its brevity and general ability to explain a majority of the variance when modeling health outcomes or behaviors. Although the psychometric properties of multidimensional assessments have been identified for some immigrant populations, the short multiple‐item measure is widely used across immigrant subgroups. National surveys such as the National Health Interview Survey, the American Community Survey, the National Health and Nutrition Examination Survey, the Current Population Survey, and the National Survey of Children's Health ask at least one or more of the questions contained in the short multiple‐item measure mentioned below. When there is concern that a survey instrument may take too long for a participant to complete in a predetermined timeframe, the short multiple‐item measure can be used to quickly assess an individual's acculturation level.
In order to assess acculturation level using a brief measure, researchers should consider collecting data on nativity and the number of years an individual has lived in the United States. Nativity is either asked as “In what country or territory were you born?” or “Were you born in the United States?” Although this question may be problematic in some instances because of fears of deportation, most respondents understand that the question does not ask about documentation status. Years lived in the United States is often phrased as “From the time that you first moved to the United States to today, about how many years have you lived in the mainland United States (50 states + DC)?” and is skipped for US‐born individuals. Responses can either be collected in an open‐ended fashion or as a predetermined count, ranging from zero to the current age of the individual. For some immigrants, their time in the United States may be segmented because they returned to their home country or moved to another country for a period of time. When this is likely, supplemental questions can be used to obtain a clearer measure of the exact number of years an individual has spent living in the United States. Such questions may include “Except for short vacations, do you return to your native country for part of each year?” Individuals who respond in the affirmative are then asked “For how many months per year?”
One of the most commonly used and easily assessable measures of acculturation level is language preference. This item can be asked in combination with nativity, years lived in the United States, or both to create a short multiple‐item measure. It should be noted that the preferred method would be to ask about language preference and at least one of the other two questions. Typically, language is assessed by asking, “What language(s) do you usually speak at home?” Similar to years in the United States, possible responses can be open‐ended or predetermined and listed for selection by the individual. When language preference cannot be collected by self‐report, language in which the survey or interview was conducted is often used to determine language preference. Sometimes, additional questions are asked about language preferences in other settings, such as “In general, what language(s) do you read and speak?” “What was the language(s) you used as a child?” “In which language(s) do you usually think?” and “What language(s) do you usually speak with your friends?” Potential response options for these questions can be: Only non‐English language (e.g., Spanish); non‐English language better than English; Both equally; English better than non‐English language; and Only English, utilizing Likert‐type scale values of 1 to 5, respectively. When combined with an item such as nativity, these questions can be used to identify if an individual is more acculturated (e.g., US‐born and prefers English), less acculturated (e.g., foreign‐born and prefers a language other than English), or bicultural (e.g., foreign‐born and prefers English or US‐born and prefers a language other than English). An example of how acculturation level, accessed using a short multiple‐item measure, is associated with risk factors for cardiovascular disease in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) can be found in Section 3.5.2.
These supplemental language preference questions sometimes contribute to multidimensional assessments of acculturation level. A general list of acculturation scales will not provide a sense of which are the most frequently cited by researchers. A list of scales to assess acculturation level among different immigrant populations
