Diabetes Risk and Control in Multi-ethnic US Immigrant Populations

Abstract

Purpose of Review

The goal of this review is to assess current evidence on diabetes risk and control among adult immigrants in the USA.

Recent Findings

Patterns of diabetes risk in US immigrants may reflect global diabetes trends. Asian, Black, and Latinx immigrants all see a diabetes disadvantage relative to US-born Whites. Diabetes risk in Asian immigrants also surpasses US-born Asians. Relative diabetes risk among all groups increases with time in the USA. Research to explain patterns in diabetes risk and control among immigrants has broadened from lifestyle factors to include multi-level, life course influences on trajectories of risk. Some determinants are shared across groups, such as structural racism, healthcare access, and migration stress, whereas others such as diet are embedded in sending country culture.

Summary

Current literature on diabetes in immigrant populations suggests a need to shift towards a transnational lens and macro-level social determinants of health framework to understand diabetes risk and potential prevention factors.

Introduction

In 2018, immigrants made up an estimated 13.7% of the United States (US) population, or 44.8 million people, which represents 50% of the population growth in the USA in the past 10 years [1]. Immigrants are a diverse population group arriving in the USA from all areas of the world and often driven to migrate because of harsh economic and political circumstances in their home countries. While some evidence suggests a recent decrease in immigrant population growth, the proportion of foreign-born adults in select US racial/ethnic groups (e.g., Latinxs and Asian Americans) can range from 40 to 80%. Because immigrant groups have different migration histories and social, economic, and cultural backgrounds, their health and risk profiles may also differ.

Specifically, a worldwide epidemic of type 2 diabetes (T2DM), fueled by a rise in obesity globally, results in immigrants arriving at the USA from countries with growing cardiometabolic risk [2, 3]. Although the “healthy immigrant effect” is a phenomenon describing immigrants’ apparent health advantage compared to their US-born counterparts, the healthy immigrant effect is not universally evident in diabetes research. Upon arrival to the USA, Black and Asian immigrants see a marked diabetes disadvantage relative to US-born Whites [4, 5]. Historically, Latinx immigrants have had a diabetes advantage over US-born Whites, but the most recent data suggests that this is no longer the case, possibly due to global diabetes trends or to earlier under-diagnosis [4, 6]. Among all groups, the foreign-born advantage erodes with longer duration in the USA, although patterns vary across ethnic subgroups and countries of origin. In regard to gestational diabetes, an “early warning signal” for T2DM, many Latinx and Black immigrant groups are also at increased risk [7]. Therefore, the actual picture of diabetes risk and control in immigrant populations is complex, with both advantages and disadvantages, potentially varying by ethnic group, social experience, time in the USA, and transnational life experiences.

In this narrative review, we adapt a general framework for understanding immigrant health to diabetes research. The framework incorporates a multi-level, life course approach to understand the diabetes disease continuum in immigrant groups (Fig. 1) [8]. Our framework proposes multiple domains relevant to migration, such as sending country conditions, social adjustment, neighborhood context, and health policy, which may contribute to a life course trajectory of T2DM risk among immigrants. These domains may take more salience at different stages of a person’s life and independently or jointly “intersect” to influence diabetes risk. Under each domain, we explore research conducted over the past 5 years across the diabetes continuum: early life determinants and risk factor prevalence, gestational diabetes, prediabetes, T2DM diagnosis, and disease management (Table 1). Our review uses a multi-ethnic perspective instead of focusing on one ethnic group, such as Latinxs or South Asians, to describe commonalities to the immigrant experience and go beyond solely cultural explanations for T2DM risk patterns. In doing so, our review sheds light on the multiple ways that biologic, behavioral, and social causes may interact to produce diabetes risk and further inform clinical, public health, and policy interventions for primary prevention and treatment in immigrant populations.

Fig. 1.

Conceptual framework of the diabetes continuum in multi-ethnic US immigrant populations

Table 1.

Recent notable research in diabetes risk and control in US immigrant populations

Study	Immigrant population	Study design	Outcomes/findings
Sending country and migration experience
Utumatwishima JN et al. J Racial Ethn Health Disparities. 2018	African immigrants (n = 85) in the Africans in America study	Cross-sectional study; allostatic load score (ALS) developed with NHANES data to assess stress due to reasons for migration	Biological stress varies by reason for immigration (lowest ALS = family reunification and lottery winner; highest ALS = study, work, asylum/refugee) and may be mitigated by maintaining family unity. Reason for immigration is likely to influence health.
Social adjustmen
Al-Sofiani ME et al. Diabetes Res Clin Pract. 2020	South Asians (SA, n = 849) in the MASALA study	Cross-sectional analysis of acculturation and cardiometabolic outcomes	SA women who had preference for US culture or both cultures had a more favorable cardiometabolic profile compared to women with a preference for SA culture. Acculturation was not significantly associated with cardiometabolic health in men.
Engelman M, Ye LZ. Adv Med Sociol. 2019	Latinx, Black, Asian, and White adults (N = 468,415) who completed NHIS	Cross-sectional analysis of NHIS diabetes diagnosis and nativity	All non-White, foreign-born groups (Latinx, Black, and Asian) regardless of nativity see a diabetes disadvantage relative to US-born Whites, and this disadvantage increases with time of residence in the USA.
Horlyck-Romanovsky MF et al. J Racial Ethn Health Disparities. 2019	African-born Blacks and Caribbean-born Blacks (N = 3069)	Cross-sectional analysis of NYC Community Health Surveys to estimate odds of obesity and diabetes	Africans had lower adjusted odds of obesity, but there was no difference in diabetes odds between African and Caribbean groups. Longer time in the USA was associated with higher risk of diabetes, but did not reach statistical significance.
Social supports
McConatha JT et al. J Cross Cult Gerontol. 2020	Middle Eastern immigrants (N = 28)	Semi-structured interviews on diabetes illness management	Patients benefit from family and community support in the management of their illness. Even in the presence of strong family and social support, patients report increased feelings of isolation due to managing a complex illness requiring many lifestyle changes.
Baghikar S et al. J Immigr Minor Health. 2019	Mexican-Americans (N = 27) living in Chicago	Semi-structured interviews on diabetes medication adherence	Financial constraints, ineffective provider communication, concerns regarding negative impact of diabetes medication, and concerns about medication effectiveness were barriers to adherence. Family support was an important facilitator to medication adherence.
Neighborhood context
Grigsby-Toussaint DS et al. Ethn Dis 2015	National sample of Latinxs	Cross-sectional analysis of the Behavioral Risk Factor Surveillance System	Segregation indices representing hyper-segregated, segregated, and non-segregated cities (Metropolitan Statistical Areas) were not associated with self-reported diabetes.
Socioeconomic position
Casagrande SS et al. Diabetes Res Clin Pract. 2018	Latinx adults (N = 3384) in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)	Baseline study questionnaires of prospective cohort on factors associated with undiagnosed diabetes	Individuals from Cuba and South America had higher odds of being undiagnosed with diabetes. Individuals with a higher odds of being undiagnosed were also women, those with no health insurance, and individuals who received no healthcare in the past year.
Commodore-Mensah Y et al. J Racial Ethn Health Disparities. 2018	African Americans (n = 36,881), African immigrants (n = 1660), and Afro-Caribbean immigrants (n = 2297)	Cross-sectional analysis of NHIS on socioeconomic factors, hypertension, and diabetes prevalence	Social determinants associated with hypertension and diabetes differed by ethnicity. In African immigrants, having health insurance was associated with higher odds of hypertension and diabetes diagnoses.
Health practices and knowledge
Li-Geng T et al. Health Equity. 2020	East Asian Americans (EAAs)	A mixed-methods systematic review to examine EAAs’ perspectives on education interventions (16 studies)	Beliefs about food, beliefs about social roles, and access to culturally competent care play an important role in dietary self-management of T2DM among EAAs.
Magny-Normilus C, Whittemore R. J Immigr Minor Health. 2020	Haitian immigrants (HIs)	Integrative review on T2DM research in the Haitian immigrant population (14 studies)	HIs had higher HbA1c, less healthcare utilization, and higher perceived emotional/psychological stress compared to other ethnic groups, despite better self-management and dietary quality.
Health policy and systems
Chasens ER et al. Prev Med. 2020	US citizens and non-citizens (N = 2702)	Cross-sectional analysis of NHANES	Non-citizens and uninsured persons were nearly twice as likely to have poor glycemic management than US citizens by naturalization and insured individuals, respectively.
Martinez-Donate AP et al. Med Care. 2020	Mexican migrants (N = 2412) from Project Migrante with and without US migration experience	Cross-sectional analysis of survey data on healthcare access and utilization and health status	Mexicans with migration experience to/from the US and deported migrants reported being less likely to have health insurance and healthcare receipt, but more likely to report being overweight/obese and diagnosed with diabetes.
Racism and ethnic discrimination
LeBrón AMW et al. J Immigr Minor Health. 2019.	Immigrant and US-born Latinx individuals (n = 222) in the REACH Detroit Partnership community health worker diabetes intervention study	Baseline interviews on discrimination and health status	Racial/ethnic discrimination was positively associated with depressive symptoms and diabetes-related distress. Racial/ethnic discrimination had a significant mediating effect on HbA1c through diabetes-related distress.
Lopez WD et al. J Immigr Minor Health. 2017	Latinx immigrants participating in Encuesta Buenos Vecinos (“Good Neighbors Survey”) before (n = 351) and after immigration raid (n = 151)	Community survey of a Latino population, examining the health implications of an immigration raid	Immigrant responses after the raid were associated with higher levels of immigration enforcement stress and lower self-rated health scores.
Gestational diabetes and intergenerational transmission
Janevic T et al. Ann Epidemiol. 2018	US-born and immigrant women (N = 565,839) identifying as non-Hispanic, Black, Hispanic, non-Hispanic White, or Asian	Retrospective analysis of birth records, GDM diagnosis, and other factors	Immigrant women had higher risk of GDM than US-born women, while the risk for overweight/obesity was lower.

Sending Country and Migration Experience

The migration process connects life course exposures and transnational exchanges from immigrants’ sending and receiving countries to explain immigrant health. In 2010, the World Health Organization declared that the movement of people across national boundaries influences economic development, labor, and population health, posing potent consequences for the burden of non-communicable diseases, including T2DM [9].

Sociopolitical factors shape early life experiences in immigrants’ sending countries prior to migration, and experiences of poverty, job security, and lack of education, among other determinants, structure the circumstances of and motivations for transnational migration. After migration, immigrants incorporate their sending and receiving countries’ lived experiences in parallel, for example through remittances or traveling for healthcare [10]. As such, health and social policies within and between countries influence diabetes risk and care. For example, a restrictive immigration climate may exacerbate food insecurity in immigrant communities without sufficient economic means, thereby increasing risk for metabolic disorders due to inadequate caloric intake [11]. Two areas of research on pathways by which these structural determinants influence biologic risk in immigrants revolve around the global epidemic of diabetes and migration stress.

The global epidemic of diabetes has important implications for sending country influences on diabetes risk in immigrant groups in the USA. The coexistence of undernutrition and overweight, obesity, or diet-related non-communicable diseases has become increasingly frequent in low- and medium-income countries [12–14]. This phenomenon, known as the double burden of disease, occurs across the life course of individuals and coexists in the same households and communities of immigrants as they emigrate into the USA [15]. It has been widely accepted that poor-quality diet and unbalanced energy intake, driven by urbanization and fast food marketing, likely cause the coexistence of undernutrition and overnutrition states [16]. Exposure to malnutrition during critical periods before migration can result in metabolic programming to induce risk for chronic diseases later in life. In a state of undernutrition, the body diverts energy through complex hormonal and neurological pathways from growth and health, to survival and potential reproduction [12]. The cumulative impact of longer exposure to hormonal dysregulation in sending countries may create a more pronounced risk for obesity and diabetes in adults once they arrive in the USA.

A second recent area of research is related to migration experience. Allostatic load score (ALS) has been proposed as a proxy for migration stress. ALS is calculated using a combination of biomarkers meant to represent the “wear and tear” on the body caused by stress [17, 18]. Among African immigrants, increased duration of stay in the USA and older age at immigration are associated with increased ALS [19] and diabetes risk [20]. High-risk reasons for immigration, such as seeking asylum or being a refugee, have also been associated with ALS and confer risk for metabolic dysregulation seen in T2DM. Huffman and colleagues [21] found that compared to US-born Blacks, Haitian Americans report higher rates of perceived stress concerning diabetes and cardiovascular disease, although they did not explicitly examine country of birth or migration history. While biological stress varies by reason for immigration, high-risk migration experiences may be mitigated by maintaining family unity [20]. Thus, a transnational lens urges us to consider the sociopolitical context under which risk emerges and the need for cross-national prevention efforts.

Social Adjustment

Social adjustment experienced by immigrants may include changes in social and economic status, change in available social support, and intergenerational conflict. Length of time in the USA, often used as a measure for social adjustment, reflects exposure to US systems and norms and degree of integration into mainstream cultural practices [22]. Time in the USA has been studied extensively in immigrant health research, but recent research delves deeper into trying to understand descriptive trends and offers potential explanations.

Four recent studies show an increased risk of diabetes with increasing time in the USA among Black, Latinx, and Asian immigrants [4, 5, 23, 24]. Two of these studies evaluated the reasons for these trends, in which obesity and education explained the foreign-born advantage for Black and White but not Latinx adults in one study [4]. The second found that language acculturation did not explain increases in risk with increasing time in the USA [23].

Only one recent study employed more refined measures of acculturation. In the “Mediators of Atherosclerosis in South Asians Living in America” (MASALA) study [25], which analyzes acculturated and non-acculturated South Asian groups, the authors found that women who were more integrated or assimilated had a lower prevalence of diabetes, prediabetes, and impaired fasting and 2-h glucose levels compared to women with higher cultural affinity. No significant association between acculturation and cardiometabolic risk was observed in South Asian men in the study. In addition to time in the USA, intergenerational differences in diabetes risk have also been studied as a surrogate measure of acculturation. However, as with “time in the USA,” such differences may represent a wide variety of social and environmental risks beyond the adoption of US cultural practices. Most recently, a 2015 study of four generational cohorts of Mexican adults in California found that foreign-born adults with diabetes had poorer quality of management, including receiving an eye examination for diabetic retinopathy screening and routine HbA1c test [26]. Taken together, these two studies demonstrate that more in-depth studies beyond time in the USA are needed to better inform diabetes interventions for disease prevention and control.

Social Supports

Social support is known to play an important role in behavior change and disease management. In immigrant health research, the degree of cultural identity, extended family, employment, and other important social networks are essential to consider in diabetes care.

Culturally specific education and peer or family support were identified as facilitators for Hmong and Haitian immigrants’ experience with diabetes education, while language and stress served as barriers [27, 28]. Many studies employ qualitative methods and support the inclusion of extended family and neighborhood members as important elements of successful diabetes management [29] in immigrant communities [30, 31]. Cultural beliefs of family harmony and social cohesion within an ethnic group may serve as potential intervention targets for knowledge, management, and/or prevention of diabetes.

Despite these apparent positive impacts of social support, other findings provide additional insights and contrary findings. Recent research in Middle Eastern immigrants demonstrates that some aspects of social contacts can increase stress for adults with diabetes [32]. For example, social events at which there is ethnic food served outside of one’s diet plan for diabetes control can be particularly stressful and serve as a barrier to disease self-management. Follow-up studies on the MASALA cohort showed that neighborhood social cohesion, degree of connectedness, and solidarity within one’s surroundings were not associated with the prevalence of T2DM in South Asians [33]. In sum, new research has unveiled the complexities in social support networks that enable or hinder health behaviors necessary for diabetes prevention and management.

Neighborhood Context

A sizeable body of literature demonstrates how social and physical features of one’s neighborhood influence diabetes risk and control [34]. Particularly salient to immigrants are ethnic enclaves, which are thought to have many health-enhancing effects, including stronger social networks and cohesion, and can make immigrants more resilient to the stress of immigration [35, 36].

Several recent studies examine neighborhood context and diabetes risk and control among immigrants, in addition to the MASALA follow-up study on neighborhood social cohesion mentioned prior. Living in an ethnic enclave is not associated with a protective effect of T2DM in Latinxs [37] or Asian and Pacific Islanders [38], although the researchers did not test associations among foreign-born Latinxs or Asians specifically. Ethnic enclaves may also be the product of racial or ethnic segregation, a manifestation of structural racism, and may negatively influence diabetes risk; thus, a confluence of negative and positive health effects may be producing these null findings. In fact, the ethnic enclave studies’ findings are in line with a review of research on neighborhood segregation and T2DM, which concludes that little evidence of a relationship has been identified thus far [39].

Socioeconomic Position

Socioeconomic position (SEP) markers such as education, employment, and housing are interwoven into the immigrant life course and serve as fundamental causes of other risk factors in the development of diabetes and its management [40]. Socioeconomic position may have different mediating effects on health in immigrant versus US-born populations—for example, in some low- and middle-income countries, smoking may be a health behavior observed in wealthier individuals, whereas in the USA, it is more commonly practiced among individuals of lower socioeconomic position.

The complexity in interpreting results and measures of socioeconomic position has come to light in recent years. When comparing African American, African immigrant, and Afro-Caribbean immigrant groups, Commodore-Mensah and colleagues report that the highest prevalence of diabetes was observed in African Americans [41], where a higher level of education was associated with lower odds of a diabetes diagnosis. Meanwhile, among African immigrants, having health insurance and lower education were associated with higher odds of diabetes diagnosis, and a higher level of education was associated with lower odds of a diabetes diagnosis. Little is known about how this difference in education and its effects evolves longitudinally across an immigrant’s life course. Similarly, Divney et al. showed the role of occupation in shaping diabetes prevalence among Latinxs [42].

Increasing insurance coverage provides significant opportunities for reducing diabetes disparities in immigrant communities. In the “Africans in America Study,” African immigrants had a higher prevalence of undiagnosed diabetes (8%) and prediabetes (35%) than African Americans (0% undiagnosed diabetes and 22% prediabetes) [43]. The International Diabetes Federation also estimated that Sub-Saharan Africa has the highest (78%) percentage of undiagnosed diabetes worldwide, which may be reflected in African immigrants in the USA. Still, it is plausible that diabetes prevalence is underestimated in African immigrants and Afro-Caribbean immigrants due to limited access to healthcare once they arrive in the USA. This hallmark study showed that African immigrants who had health insurance were three times more likely to have diabetes than those without health insurance, and higher levels of education were associated with insurance coverage. Similarly within the Latinx community, compared to people of Mexican heritage, immigrants from Cuba and South America have higher odds of being undiagnosed. Typically, those without health insurance, individuals who have not received healthcare within 12 months, and women have been shown to have a higher likelihood of having undiagnosed T2DM [44]. Oftentimes, high health insurance costs are a significant contributor to not possessing health insurance [45]. Moreover, federal laws restrict eligibility for government-based insurance programs. The eligibility standards outlined by the Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) of 1996 and Affordable Care Act (ACA) restrict Medicaid eligibility to permanent residents, those seeking humanitarian relief, and certain immigrants with permission to live and work in the USA [46]. Some states also impose a 5-year waiting period on lawfully present immigrants. These laws pose substantive threats to health access to many categories of immigrants, coupled with the burden to meet additional eligibility criteria and apply to programs. Overall, the relationship between socioeconomic position and healthcare access impacts the circumstances in which immigrant populations live, work, and deal with T2DM.

Health Practices and Knowledge

Knowledge, attitudes, and practices with respect to health, disease, and healthcare treatments and utilization, including indigenous ethnomedical systems, may influence diabetes risk and management. Such differences may reflect either socioeconomic position, macro-level health policies, and/or ethnic differences more closely tied to culture.

Health practices and knowledge, as drivers of diabetes risk and management among immigrants, are active research areas, most of which use qualitative methods. A study of Congolese immigrants identified the perception that eating American fast food can increase one’s risk of diabetes and found that Congolese identity was linked to healthy food choices [47]. Among East Asian American immigrant communities, diet regimens required for diabetes management tend to disrupt social harmony and make East Asian Americans feel burdensome to others [48]. In other studies, some Spanish-speaking Latinx immigrants attributed developing the disease to strong emotions and viewed T2DM as a serious disease [49]. Although many Latinxs reported a common understanding on the importance of exercise and diet in T2DM self-management, other aspects such as medication adherence are not well-understood. One study by Njeru et al. compared Somali and Latinx immigrants and found similarities in barriers to optimal diabetes management, including physical activity, glucose self-monitoring, and negative perceptions of diabetes [50]. Another study with Haitian immigrants showed that self-reliance, spirituality, nostalgia for home country, and a desire for positive patient–provider relationships altered health knowledge and behaviors [51]. Haitian immigrants also reported better dietary quality, less healthcare utilization, and higher perceived emotional or psychological stress than other ethnic groups [52]. Overall, cultural beliefs distinct to a particular region of origin or multi-ethnic group may influence a wide range of diabetes health practices.

Health Policy and Systems

While differences in risk and management exist among migrant communities, the shared experiences of immigration and broader policies and systems play a significant role in diabetes burden among immigrants. Non-citizenship and lack of health insurance have been associated with increased risk for diabetes and poor glycemic management [53]. Martinez-Donate et al. examined health outcomes and healthcare access of Mexican migrants traversing the Mexican border region [54]. Their findings showed that immigrants with US migration experience and deported migrants had lower levels of health insurance and healthcare utilization, and higher diabetes incidence compared to their migrant counterparts without US migration experience. Furthermore, in a study examining the associations between access to care, acculturation, and glycemic control, one of the most significant predictors of glycemic control was access to primary care [55]. Thus, systems that create barriers to or withhold access to adequate diabetes care in US immigrants place these communities at an increased risk of poor diabetes outcomes.

The provision of healthcare in a respectful and culturally sensitive manner is vital to reducing inequities in diabetes care. Perceived barriers to effective T2DM self-management in Korean-Americans and Latinx immigrants include high cost of care, language issues, limited access to healthcare resources, negative interactions with healthcare providers, cultural stigma, and the complexity of the disease [49, 56]. In a study with urban, low-income Mexican-Americans with diabetes, concerns regarding the effectiveness and negative impact of diabetes medication were also prevalent [31]. Dissatisfaction with ineffective provider communication and not being able to pay for medication were other important barriers to adherence. Conversely, having bilingual and bicultural resources has been shown to ease the diabetes-related distress and result in significant reductions in hemoglobin A1C [48]. Thus, training on “cultural humility” in providing care presents a compelling and mutable factor to improve diabetes risk and management.

Racism and Ethnic Discrimination

Structural racism and perceived racial–ethnic discrimination can have considerable effects on immigrant health. Previous literature suggests that the social statuses to which individuals attribute their experiences of discrimination may shape health differently [57]. In US-born groups, discrimination contributes to lower levels of self-care, mistrust of clinicians, and underutilization of healthcare services [58]. Institutional and personally mediated racism, including heightened immigration enforcement and involvement of local law enforcement agencies, enhances exposure to racialized stressors and limits undocumented immigrants’ access to health-promoting resources [59–61]. Previous studies also link anti-immigration policies with declines in health and healthcare utilization for US-born and immigrant Latinxs [62–66]. Anti-immigration sentiments, coupled with barriers to healthcare access, exacerbate diabetes risk.

Robust literature documents associations of self-reported discrimination with poorer mental health and some indicators of physical health [67–69]. Racial and ethnic discrimination is positively associated with depressive symptoms and diabetes-related distress for Latinxs with T2DM, two outcomes associated with worse diabetes self-management and glycemic control [70, 71]. Importantly, racism and ethnic discrimination have a significant mediating effect on HbA1c through diabetes-related distress [59]. Evidence indicates that physiologic responses to chronic stressors contribute to the protracted elevation of cortisol levels and enhanced metabolic stress, dysregulating glucose control [72]. The association of racial and ethnic discrimination with distress, glycemic control, and hormonal dysregulation suggests the need to consider complex associations of chronic stressors such as discrimination with multiple, interconnected diabetes-related outcomes.

Gestational Diabetes and Intergenerational Transmission

It is well documented that women with gestational diabetes mellitus (GDM) have a 30 to 70% risk for developing T2DM within 10 years [73–75]. GDM, defined as glucose intolerance first recognized during the second or third trimester of pregnancy, is the most common pregnancy complication affecting women [76, 77] and presents substantiated risk for adverse maternal outcomes and long-term sequelae for mothers and their offspring [78]. Studies from the UK, US, Europe, Canada, and Australia have shown that immigrant women have a high incidence of GDM with adverse pregnancy outcomes compared to women from receiving countries [79]. In particular, women who are South Central Asian, American Indian, or Latina have been shown to have the highest risk of developing GDM [80–85], where Latinas have a 30–60% higher risk for developing GDM [7]. Notably, gestational diabetes incidences vary among immigrant groups. In a study of immigrant women conducted by Janevic et al., the percentage of women with gestational diabetes was the lowest among Sub-Saharan African immigrant women (4.5%) and the highest among women from South Central Asia (15.8%) [86]. While differences in relative risk for GDM associated with BMI ≥ 25 kg/m² have been reported in US-born and foreign-born women [87], GDM risks across racial/ethnic groups do not appear to be fully explained by pre-pregnancy BMI differences [7, 88, 89].

Known risk factors for GDM include a history of GDM in previous pregnancies, prior large-for-gestational-age (LGA) baby, family history of type 2 diabetes, greater weight gain during pregnancy, and high maternal BMI before conception. The increased risk of diabetes and GDM is also associated with dietary patterns low in fiber and high in total and saturated fat, red and processed meat, and glycemic load [90, 91]. These factors demonstrate significant features of the social environment, such as living within ethnic enclaves, which influence gestational diabetes risk [92]. Although as described earlier ethnic enclave residence is not associated with T2DM, among South Central Asian and Mexican women, living in a residential ethnic enclave is associated with an increased odds of gestational diabetes [86]. Similar to social supports examined in T2DM diabetes literature, social context may have variable effects on GDM and T2DM risk and management.

It has been suggested that a woman’s early life environment may influence her risk of metabolic diseases later in life [93, 94], providing serious implications for intergenerational transmission of diabetes risk. The “Barker hypothesis” proposes that malnutrition during fetal development, infancy, and early childhood may permanently change the structure and function of the body [93, 95]. Permanent changes in glucose–insulin metabolism reduce the capacity for insulin secretion and induce insulin resistance, which, combined with age, obesity, and physical inactivity, determine the development of type 2 diabetes [96]. Because most migration is economically driven, women born in poorer countries are more likely to have experienced nutritional deficiencies in fetal or early life compared to when they give birth in a higher-income country, and hence may be more prone to metabolic disorders, including T2DM. The literature on GDM in immigrant women provides insights into fetal programming and intergenerational transmission of diabetes risk and provides one potential explanation for increasing risk of T2DM across multigenerational immigrant populations.

Conclusions

Current literature on diabetes in immigrant populations suggests a need to shift towards a transnational lens and macro-level social determinants of health framework to understand diabetes risk and potential prevention factors. The present review brings to light a more nuanced understanding of diabetes in immigrant groups than earlier research that focused primarily on the healthy immigrant effect or cultural explanations for health advantages. Although diabetes risk appears to inflate with increasing time in the USA, this finding must be understood within the context of migration history, socioeconomic position, health policies and systems, and racial and ethnic discrimination. Moreover, these broader systems interact with cultural traditions to shape health knowledge, perceptions, and practices. In summary, macro-level social and individual-level determinants interact to produce a complex chain of risk, management, and treatment for US immigrants.