Can inaccuracy of reported parental history of diabetes explain the maternal transmission hypothesis for diabetes?

Association of risk factors with type 2 diabetes: A systematic review

Diabetes is the leading cause of severe health complications and one of the top 10 causes of death worldwide. To date, diabetes has no cure, and therefore, it is necessary to take precautionary measures to avoid its occurrence. The main aim of this systematic review is to identify the majority of the risk factors for the incidence/prevalence of type 2 diabetes mellitus on one hand, and to give a critical analysis of the cohort/cross-sectional studies which examine the impact of the association of risk factors on diabetes. Consequently, we provide insights on risk factors whose interactions are major players in developing diabetes. We conclude with recommendations to allied health professionals, individuals and government institutions to support better diagnosis and prognosis of the disease.

Maternal vs paternal diabetes: The parental history is different in younger onset versus older onset type 2 diabetes

BACKGROUND

A number of previous studies exploring family history of type 2 diabetes have reported a predominance of maternal diabetes. These studies have not explicitly compared parental history of diabetes across the spectrum of disease onset from youth to later adulthood.

METHODS

Family history data from 11,467 patients with type 2 diabetes were extracted from the RPA Diabetes Centre database. Parental histories of diabetes were compared across a range of age of diagnosis strata (15-<30, 30-<40, 40-<50, 50-<60 and 60-<70 years). For the young-onset group (diagnosed between 15 and 30 years of age), associations between parental history of diabetes and the presence of cardio-metabolic risk factors and diabetic complications were also explored.

RESULTS

For the total cohort and within each age of diagnosis strata, more individuals reported maternal history than paternal history of diabetes. The young-onset group demonstrated the highest prevalence of any parental history of diabetes (60.7%), the highest combined maternal and paternal history (15.8%) and the smallest differential between maternal (25.1%) and paternal (19.7%) history of diabetes. Within the young-onset group, no significant association between parental history and cardio-metabolic risk factors or diabetic complications were identified after a median of 15.0 years of diabetes exposure.

CONCLUSION

Overall, our results demonstrate a consistent maternal excess of diabetes which could be consistent with an underlying epigenetic effect. However, the differential between maternal and paternal history is significantly lower in the young-onset group. Earlier emergence of type 2 diabetes may therefore reflect a different interaction and impact of genetic and environmental factors.

Association between parental history of diabetes and the incidence of type 2 diabetes mellitus differs according to the sex of the parent and offspring's body weight: A finding from a Japanese worksite-based cohort study

OBJECTIVE

To investigate differences in the association of parental history of diabetes with the risk of type 2 diabetes mellitus (T2DM) in the offspring according to the sex of the parent and the offspring's body weight.

METHODS

A prospective cohort study of 4446 middle-aged non-diabetic Japanese men and women were followed in Aichi Prefecture, central Japan, from 2002 to 2011. Subjects were categorized by their self-reported parental history of diabetes ("no parental history," "father only," "mother only," and "both"). The association of parental history of diabetes and incidence in the offspring was examined according to overweight status adjusted for age, sex, birth weight, smoking, alcohol consumption, physical activity, total energy intake, body mass index, and number of metabolic syndrome components.

RESULTS

During follow-up (median 8.9 years), 277 subjects developed T2DM. Parental history of diabetes was positively associated with T2DM incidence. However, stratified analysis by overweight status revealed that only maternal history was associated with increased T2DM incidence in non-overweight subjects (hazard ratio=2.35, 95% confidence interval: 1.41-3.91). While in overweight subjects, paternal history was significantly associated with higher T2DM incidence (hazard ratio=1.98, 95% confidence interval: 1.19-3.28).

CONCLUSIONS

Our results suggest that parental history of diabetes mellitus is associated with the incidence of T2DM in offspring differently according to the sex of the affected parent and the offspring's body weight.

Maternal history of diabetes is associated with increased cardiometabolic risk in Chinese

OBJECTIVE

Positive family history is associated with increased type 2 diabetes (T2D) risk, and reflects both genetic and environmental risks. Several studies have suggested an excess maternal transmission of T2D, although the underlying mechanism is unknown. We aimed to examine the association between maternal diabetes and cardiometabolic risk in the offspring.

METHODS

Parental history of diabetes and clinical data including anthropometric traits, fasting plasma glucose and insulin (FPG, FPI), blood pressure and lipid profile were collected from 2581 unrelated Chinese offspring (2026 adolescents from a population-based school survey and 555 adults from a community-based health screening programme). A subset of subjects (n=834) underwent oral glucose tolerance test to measure the glucose and insulin concentrations at 0, 15, 30, 60 and 120 min for evaluation of the areas under the curve (AUC) of glucose and insulin at 0-120 min, homoeostasis model assessment of insulin resistance (HOMA-IR) and bell-cell function, insulinogenic index, insulin sensitivity index (ISI) and oral disposition index (DI).

RESULTS

A positive parental history of diabetes was associated with increased risk of obesity (odd ratios (OR) (95% confidence interval (CI))=1.48 (1.10-2.00)), central obesity (OR (95% CI)=1.67 (1.21-2.32)), higher FPI, HOMA-IR, 2-h insulin, AUC of glucose at 0-120 min, triglycerides, reduced ISI and DI. Compared with individuals without parental diabetes, offspring with diabetic mother had significantly increased risk of obesity (OR (95% CI)=1.59 (1.07-2.35)), central obesity (OR (95% CI)=1.88 (1.23-2.88)), higher glucose levels and BP, were more insulin resistant but also had impaired first-phase insulin response and worse lipid profile. However, paternal history of diabetes had no effect on any of the studied traits, except higher body mass index, waist circumference in females and FPG.

CONCLUSIONS

Our findings suggested that maternal history of diabetes conferred increased risk of cardiometabolic abnormalities, and was associated with both insulin resistance and impaired first-phase insulin secretion. Further investigation into the mechanism of transgenerational diabetes is warranted.

Familial Clustering of Type 2 Diabetes among Omanis

OBJECTIVE

The aim of this study was to screen Omani individuals for the familial aggregation of type 2 diabetes mellitus.

METHODS

A random cohort of 1182 Omani individuals visiting the Family Medicine Clinic at Sultan Qaboos University Hospital (SQUH), Muscat, Oman, for regular medical checkup, aged ≥40 years, were sampled. Patients were categorized into three groups: (1) individuals who claim not to have diabetes and had no family history of diabetes; (2) individuals who claim not to have diabetes but had family history of diabetes; (3) individuals with diabetes. Only 16% of these Omani individuals had no diabetes and no family history of diabetes. Another separate random cohort of 234 Omani type 2 diabetes mellitus patients, from the Diabetes Clinic at SQUH, were interviewed and questioned about their family history of type 2 diabetes mellitus.

RESULTS

Ninety five percent of the patients had a family history of diabetes. Eighty percent had first degree relatives with diabetes and 46% had second degree relatives with diabetes. At least one parent with diabetes was reported among 55% of these diabetics, while maternal diabetes (55%) was found to be higher than paternal diabetes (47%). However, only 15% had both parents with diabetes. Furthermore, almost half of the 234 diabetics were having at least one of the following relatives with diabetes: brother, sister, aunt or an uncle.

CONCLUSION

The findings of this study confirm familial aggregation of diabetes among the Omani population. Compared to other populations, familial aggregation of type 2 diabetes mellitus among Omanis is relatively very high, and is perhaps due to the very high degree of consanguinity among Omanis. Since almost everyone seems to have a genetic predisposition to diabetes, the dramatic lifestyle changes over the past 25 years, could tip the population into an epidemic of type 2 diabetes mellitus.

Maternal and paternal transmission of type 2 diabetes: influence of diet, lifestyle and adiposity

OBJECTIVE

Transmission of family history of type 2 diabetes to the next generation is stronger for maternal than paternal diabetes in some populations. The aim of the present study was to investigate whether this difference is explained by diet, lifestyle factors and/or adiposity.

METHODS

We analysed 35174 participants from the Dutch contribution to the European Prospective Investigation into Cancer and Nutrition, a prospective population-based cohort (aged 20-70 years) with a median follow-up of 10.2 years. Parental history of diabetes was self-reported. Occurrence of diabetes was mainly identified by self-report and verified by medical records.

RESULTS

Amongst 35174 participants, 799 incident cases of diabetes were observed. In age- and sex-adjusted analyses, hazard ratio (HR) and 95% confidence intervals (CIs) for diabetes by maternal and paternal diabetes were 2.66 (2.26-3.14) and 2.40 (1.91-3.02), respectively. Maternal transmission of risk of diabetes was explained by diet (9.4%), lifestyle factors including smoking, alcohol consumption, physical activity and educational level (7.8%) and by adiposity, i.e. body mass index and waist and hip circumference (23.5%). For paternal transmission, the corresponding values were 2.9%, 0.0% and 9.6%. After adjustment for diet, lifestyle factors and adiposity, the HRs for maternal (2.20; 95% CI, 1.87-2.60) and paternal (2.23; 95% CI, 1.77-2.80) transmission of diabetes were comparable.

CONCLUSIONS

Both maternal and paternal diabetes are associated with increased risk of type 2 diabetes, independently of diet, lifestyle and adiposity. The slightly higher risk conferred by maternal compared to paternal diabetes was explained by a larger contribution of diet, lifestyle factors and adiposity.

[Long term outcome in children of mothers with gestational diabetes]

OBJECTIVES

To appreciate, in epidemiological studies, the impact of fetal exposure to gestational diabetes on the long term outcome of the offspring (type 2 diabetes, overweight and obesity, metabolic syndrome and neurological complications).

METHODS

A systematic search was conducted in Medline between January 1990 and April 2010. Prospective studies (follow-up of the offspring born of mothers with gestational diabetes) and retrospective studies (questionnaire about the parents'history of diabetes in diabetic patients) were searched and analysed.

RESULTS

The fetal exposure to maternal gestational diabetes is a moderate risk factor for metabolic syndrome in the offspring. But some other perinatal risk factors of metabolic syndrome carry a bigger influence. The influence of genetic factors and maternal overweight may not be easily distinguished from the impact of fetal exposure to gestational diabetes.

CONCLUSION

It remains uncertain if the control of maternal glycemia alone may be effective and sufficient to prevent the metabolic syndrome in the adult-aged offspring.

Diabetes risk assessment in Mexicans and Mexican Americans: effects of parental history of diabetes are modified by adiposity level

OBJECTIVE

Parental diabetes history is a well-known risk factor for type 2 diabetes and considered strong evidence for a genetic basis of type 2 diabetes. Whether this relationship is affected by other known risk factors, specifically obesity, remains unclear, possibly due to a relative paucity of lean diabetic patients.

RESEARCH DESIGN AND METHODS

This issue was investigated using data from a high-risk population from Mexico (National Health Survey 2000, n = 27,349), with observations replicated using U.S. citizens of Mexican descent from the National Health and Nutrition Examination Survey 2001-2002 and 2003-2004 (n = 1,568).

RESULTS

As expected, positive parental diabetes was a significant risk factor for type 2 diabetes, regardless of age, sex, or adiposity level. However, positive parental diabetes conferred greater risk in leaner individuals than in their overweight peers (P = 0.001). In other words, the effect of BMI on type 2 diabetes risk was smaller in the presence of parental diabetes history.

CONCLUSIONS

These findings suggest that parental diabetes is a stronger risk factor for type 2 diabetes in the absence of obesity. Thus, studies in lean diabetic patients could help identify type 2 diabetes susceptibility genes. This study reinforces the concept that parental diabetes and BMI are independent type 2 diabetes risk factors and suggests that glycemic screening may be helpful in assessing type 2 diabetes risk in individuals with parental diabetes history, regardless of their overweight status.

Mitochondrial and nuclear gene mutations in the type 2 diabetes patients of Coimbatore population

Involvement of mitochondrial and nuclear gene mutations in the development of type 2 diabetes (T2D) has been established well in various populations around the world. Previously, we have found the mitochondrial A>G transition at nucleotide position 3243 and 8296 in the T2D patients of Coimbatore population. This study is aimed to screen for the presence of various mitochondrial and nuclear DNA mutations in the T2D patients of Coimbatore to identify most prevalent mutation. This helps in identifying the susceptible individuals based on their clinical phenotype in future. Blood samples were collected from 150 unrelated late-onset T2D patients and 100 age-matched unrelated control samples according to World Health Organization criteria. Genotyping for the selected genes was done by polymerase chain reaction-single strand confirmation polymorphism, direct sequencing, and polymerase chain reaction-restriction fragment length polymorphism. The mitochondrial T>C transition at 8356 and nuclear-encoded GLUT1 gene mutation were found in the selected T2D patients. The T8356C mutation was found in two patients (1.3%), and the clinical characteristics were found to be similar in both the patients whereas GLUT1 gene mutation was found in seven patients. Four out of seven patients showed homozygous (-) genotype and three patients showed heterozygous (±) genotype for the mutant allele XbaI. Among these three patients, one patient was found to have elevated level of urea and creatinine with the history of kidney dysfunction and chronic T2D. Our results suggest that the T8356C and GLUT1 gene mutations may have an important role in developing late-onset T2D in Coimbatore population. Particularly, individuals with GLUT1 gene may develop kidney dysfunction at their later age.

Maternal family history of diabetes is associated with a reduced risk of cardiovascular disease in women with type 2 diabetes: the Fremantle Diabetes Study

OBJECTIVE

To investigate whether parental family history of diabetes influences cardiovascular outcomes in type 2 diabetes.

RESEARCH DESIGN AND METHODS

We studied 1,294 type 2 diabetic patients (mean age 64.1 years, 51.2% female) recruited to a community-based cohort study from 1993 to 1996 and followed until mid-2006. A data linkage system assessed all-cause and cardiac mortality, incident myocardial infarction, and stroke. Cox proportional hazards modeling was used to determine the influence of maternal or paternal family history on these outcomes.

RESULTS

A maternal family history of diabetes was reported by 20.4% of the cohort, 8.3% reported paternal family history, and 2.0% reported both parents affected. Maternal and paternal family history was associated with earlier age of diabetes onset, and maternal family history was associated with worse glycemic control. For all patients, maternal family history was significantly associated with reduced risk of all-cause mortality and cardiac mortality. When analyzed by sex, maternal family history had no effect on male patients, whereas female patients with diabetic mothers had significantly reduced hazard ratios for death from all causes (0.63 [95% CI 0.41-0.96]; P = 0.033), for death from cardiac causes (0.32 [0.14-0.72]; P = 0.006), and for first myocardial infarction (0.45 [0.26-0.76]; P = 0.003). Paternal family history status was not associated with these outcomes.

CONCLUSIONS

A maternal family history of diabetes confers relative protection against cardiovascular disease in female patients but not in male patients with type 2 diabetes. Paternal family history is associated with risks equivalent to those without a family history of diabetes. Some of the clinical heterogeneity of type 2 diabetes is related to maternal transmission effects with differential impact on male and female patients.

Racial differences in the interaction between family history and risk factors associated with diabetes in the National Health and Nutritional Examination Survey, 1999-2004

PURPOSE

We sought to determine whether the association between family history, a surrogate for genetic predisposition, and diabetes was modified by any known diabetes risk factors and if these relationships were constant across different ethnic groups.

METHODS

We examined 10,899 adults from the National Health and Nutrition Examination Survey (1999 -2004) to identify interactions between family history and clinical, demographic, and lifestyle variables for the outcome of diabetes using logistic regression analysis in racial/ethnic subgroups.

RESULTS

There was significant heterogeneity by race/ethnicity in the interaction between covariates and family history in relation to diabetes. In black (P = 0.0001) and Hispanic (P = 0.013), but not white (P = 0.75) subgroups, high-familial risk was a strong risk factor for diabetes among lean individuals but less so among overweight or obese subjects.Among blacks, high-familial risk conferred a 20-fold increased odds of diabetes among lean subjects and only a sixfold increased odds among obese individuals.

CONCLUSIONS

These findings suggest possible race/ethnic-specific differences in gene by environment interaction and identify body mass index as an important effect modifier of familial risk in diabetes in non-white populations. These findings may help guide future genetic studies and improve the utility of family history as a public health screening tool.

The effect of paternal and maternal history of diabetes mellitus on the development of gestational diabetes mellitus

BACKGROUND

There is an ongoing debate whether maternal diabetes is a more important risk factor for gestational diabetes (GDM) development than paternal diabetes.

AIM

To describe the risk of GDM associated with paternal and maternal diabetes, and to further characterise GDM women with maternal diabetes.

SUBJECTS AND METHODS

Case-control study within a population-based GDM screening program in an urban area of Hungary in 2002-2003. All GDM women (no.=133) and an age-matched control group (no.=135) with a mean age of 31 years was evaluated. Blood pressure, anthropometric data, and blood glucose values from a 75 g Oral Glucose Tolerance Test (OGTT) were recorded at 24-28 weeks of gestation. Family history data were by self-report.

RESULTS

Known paternal diabetes was not related to GDM risk [odds ratio (OR) 0.83, 95% confidence interval (CI) 0.35-2.00]. Known maternal diabetes (OR 2.90, 95% CI 0.99-8.49) and diabetes in the maternal line (OR 2.83, 95% CI 1.16-6.89) were both related to GDM after adjustment for body mass index (BMI). GDM women with known maternal diabetes had a higher BMI, 31.6 [9.1] kg/m2 median [interquartile range], than GDM women with or without diabetes in the maternal line, 26.1 [4.9] and 26.3 [6.1] kg/m2, respectively, while figures for fasting glucose during OGTT were 5.2 [0.7] vs 4.4 [1.1] vs 4.9 [0.8] mmol/l respectively (all p<0.05).

CONCLUSIONS

Maternal history of diabetes and history of diabetes in the maternal line seems to be a stronger predictor of GDM than paternal history.

Sex Differences in Heritability of Ischemic Stroke

Background and Purpose— Using data from Oxfordshire, UK, we recently showed that women are more likely than men to have a family history of stroke in female versus male first degree relatives. To test the generalizability of this finding, we did a comprehensive systematic review of all available published and unpublished data.

Methods— Studies were included in the present review if they reported the frequency of family history of stroke in relation to sex of parent or proband. Where necessary, we contacted authors of studies to obtain unpublished data. Data from the Oxford Vascular Study (OXVASC) and 3 other Oxford cohorts (1925 patients) were secondarily pooled with the data from other studies.

Results— We obtained data from 18 studies (7941 patients), including unpublished data from 7 studies. Female probands were slightly more likely to have a parental history of stroke than male probands (pooled OR=1.15; 95% CI: 1.03 to 1.29; P (sig) =0.028; P (het) =0.45). Maternal history of stroke was more common than paternal history (pooled OR=1.25; 1.15 to 1.37; P (sig) <0.00001; P (het) =0.12). However, the maternal excess was only present in female probands (pooled OR=1.47; 1.27 to 1.70; P (sig) <0.00001; P (het) =0.11). In contrast, male probands were no more likely to have maternal than paternal history of stroke (pooled OR=1.02; 0.88 to 1.17, P (sig) =0.43; P (het) =0.09).

Conclusions— Women with stroke are more likely than men to have a parental history of stroke, which is accounted for by an excess maternal history of stroke. This finding could be explained by sex-specific genetic, epigenetic, or nongenetic mechanisms.

Familial history of type 2 diabetes in patients from Southern Brazil and its influence on the clinical characteristics of this disease

OBJECTIVE

To investigate the presence of maternal and paternal history of type 2 diabetes mellitus (DM) in relatives of 644 type 2 diabetic patients from Southern Brazil, and also to evaluate its influence on the clinical characteristics of this disease.

PATIENTS AND METHODS

Familial history of type 2 DM was investigated by a questionnaire. The maternal and paternal history was investigated over two generations. Complete data sets on familial history were obtained from 396 patients.

RESULTS

In general, 76.6% of the patients reported at least one first-degree affected relative. Besides, 31.6% of the patients reported a maternal history of type 2 DM and 12.6% reported a paternal history. Patients with maternal and/or paternal history presented a lower age at type 2 DM diagnosis when compared to patients without familial history. In addition, patients with only paternal history presented a higher frequency of hypertension than patients with no familial history.

CONCLUSIONS

This study suggests that there is a significant maternal effect in the transmission of type 2 DM in Southern Brazil, and that most of the clinical characteristics of this disease do not differ between patients with or without familial history of type 2 DM.

Heritability of ischaemic stroke in women compared with men: a genetic epidemiological study

BACKGROUND

Ischaemic stroke is partly heritable. However, although the genetic and non-genetic factors responsible could be sex-specific, interactions between the sex of the parent affected and the sex of the proband or affected siblings are unknown. We sought to assess the relation between the sex and phenotype of affected probands and the sex of affected first-degree relatives.

METHODS

We determined the prevalence of history of stroke in the mother, father, and other first-degree relatives in female and male probands with ischaemic stroke or transient ischaemic attack in the population-based Oxford Vascular Study (OXVASC). We validated our findings using unpublished individual patient data from two independent Oxford studies.

FINDINGS

In OXVASC, detailed family history was available in 806 (93%) probands. Female probands were more likely than males to have at least one affected first-degree relative (146/423 vs 104/383; OR 1.4, 95% CI 1.1-2.0, p=0.02) due entirely to an excess of affected female relatives in female probands (female relative vs male relative OR=1.7, 1.3-2.4, p=0.0004; female only vs male only OR=2.1, 1.4-3.1, p=0.0001). Maternal stroke was more common than paternal stroke in female probands (OR=1.8, 1.2-2.7, p=0.001) but not in males (OR=1.1, 0.7-1.7, p=0.38), and female probands were more likely than males to have an affected sister (OR=3.1, 1.5-6.7, p=0.004) but not an affected brother (OR=1.1, 0.6-2.1, p=0.80). Ages at first stroke were also correlated within families among affected females (r=0.36, p=0.004) but not among affected males, such that the excess of affected female relatives of female probands was greatest when the difference in age at first stroke was less than 5 years (OR=3.7, 1.6-8.6, p=0.0007) and fell as the age difference increased (p for trend=0.004). These findings were independent of traditional risk factors and stroke subtype. Data from the other Oxford studies confirmed the excess maternal history of stroke in female probands (OR=2.3, 1.5-3.8, p<0.00001) and the lack in males (OR=1.0, 0.7-1.4, p=0.58).

INTERPRETATION

Heritability of ischaemic stroke is greater in women than in men, with an excess of affected mothers and affected sisters in female probands independent of traditional vascular risk factors, which could be explained by sex-specific genetic, epigenetic, or non-genetic mechanisms.

Association between parental histories of hypertension, diabetes and dyslipidemia and the clustering of these disorders in offspring

BACKGROUND

Familial aggregation of hypertension, diabetes and dyslipidemia has been well reported. However, only a few studies have assessed to what extent parental histories were involved in the clustering of these diseases.

METHOD

In 2002, associations between parental histories of hypertension, diabetes and dyslipidemia and the clustering of high blood pressure, hyperglycemia and dyslipidemia in individuals were assessed on the basis of 5010 Japanese men and women aged 33-66 years. Risk factor clusters were defined as those having at least two of the three clinical disorders.

RESULTS

Compared with persons with no parental history of the three diseases, those who had 1, 2 and 3 or more parental histories had risk factor clusters, 1.25 (95% CI: 1.07, 1.47), 1.46 (95% CI: 1.16, 1.84) and 1.41 (95% CI: 0.95, 2.11) times higher, respectively, after adjusting for confounding factors. ORs by 1, 2 and 3 of maternal history were 1.33 (95% CI: 1.12, 1.58), 1.65 (95% CI: 1.16, 2.35) and 1.69 (95% CI: 0.64, 4.42), respectively (trend P < 0.001). However, the number of paternal history was not associated with risk factor clusters.

CONCLUSION

We conclude that familial history, particularly maternal history, is an important aid to prevention strategy and public health practice for metabolic disorders.

Data-mining analysis suggests an epigenetic pathogenesis for type 2 diabetes

The etiological origin of type 2 diabetes mellitus (T2DM) has long been controversial. The body of literature related to T2DM is vast and varied in focus, making a broad epidemiological perspective difficult, if not impossible. A data-mining approach was used to analyze all electronically available scientific literature, over 12 million Medline records, for “objects” such as genes, diseases, phenotypes, and chemical compounds linked to other objects within the T2DM literature but were not themselves within the T2DM literature. The goal of this analysis was to conduct a comprehensive survey to identify novel factors implicated in the pathology of T2DM by statistically evaluating mutually shared associations. Surprisingly, epigenetic factors were among the highest statistical scores in this analysis, strongly implicating epigenetic changes within the body as causal factors in the pathogenesis of T2DM. Further analysis implicates adipocytes as the potential tissue of origin, and cytokines or cytokine-like genes as the dysregulated factor(s) responsible for the T2DM phenotype. The analysis provides a wealth of literature supporting this hypothesis, which—if true—represents an important paradigm shift for researchers studying the pathogenesis of T2DM.

Lack of excess maternal transmission of type 2 diabetes in a Korean population

The purpose of this study was to assess the familial clustering of type 2 diabetes and to investigate the presence of excess maternal transmission of type 2 diabetes in Korea. The medical records of 56,492 subjects (31,680 men and 24,812 women), who attended the Health Promotion Center were examined. The subjects were questioned about their parents' diabetes status. All study subjects were classified into the three groups (normal fasting glucose (NFG), impaired fasting glucose (IFG), and diabetes). Offspring with paternal diabetes (odds ratio 2.54, 95% CI 2.22-2.91, P < 0.001) and those with maternal diabetes (odds ratio 3.10, 95% CI 2.76-3.49, P < 0.001) were at increased risk for diabetes when compared to subjects without parental diabetes and adjusted for other clinical and biochemical variables. Offspring with bilineal parental diabetes were at a greater risk for diabetes (odds ratio 6.09, 95% CI 4.55-8.16, P < 0.001) when compared to subjects without parental diabetes. In both genders, offspring with maternal diabetes showed no increased risk for diabetes (odds ratio 1.22, 95% CI 0.92-1.37, P + 0.266 in men; odds ratio 1.31, 95% CI 0.95-1.81, P = 0.104 in women) when compared with those with paternal diabetes. The data suggested that parental type 2 diabetes was an independent risk factor for offspring type 2 diabetes in this Korean population. Excess maternal transmission of type 2 diabetes was not observed.

Family history of diabetes as a potential public health tool

Given the substantial morbidity and mortality associated with type 2 diabetes, it is important that public health seek ways to delay or prevent the onset of this condition. Risk factors for type 2 diabetes are well established and include underlying genetic susceptibility. Despite this knowledge, as well as significant advances in understanding the human genome, the prevalence of type 2 diabetes continues to rise at an alarming rate. Because type 2 diabetes is a complex condition involving a combination of genetic and environmental factors, DNA testing for susceptibility genes is not yet warranted. However, because family history reflects genetic susceptibility in addition to other factors, it may be a useful public health tool for disease prevention. When evaluating family history as a public health tool, several important issues need to be considered, including the analytic and clinical validity and the clinical utility of using family history as a screening tool. These issues as well as a review of the epidemiologic evidence evaluating family history as a risk factor will be reviewed.Overall, a family history approach appears to be a promising new public health tool to fight the growing epidemic of diabetes in the United States. Adequate levels of funding to further evaluate this approach and to develop appropriate tools should be made available for research activities focused on this important area.

Epidemiology of diabetes among Arab Americans

OBJECTIVE

To examine the prevalence of diabetes and glucose intolerance by age and sex in the Arab-American community of Dearborn, Michigan.

RESEARCH DESIGN AND METHODS

Participants were randomly selected adult Arab Americans, 20-75 years of age, from randomly selected households in Dearborn, Michigan. Demographic and anthropometric data were recorded. Glucose tolerance was assessed with 2-h 75-g oral glucose tolerance tests and classified according to 1997 American Diabetes Association and 1998 World Health Organization criteria.

RESULTS

A total of 626 eligible adults were selected, and 542 participated (87% response rate). Because prevalence increases with age and the overall response rate for women (328/352; 93%) was higher than that for men (214/274; 78%), prevalence rates were adjusted for age and sex. The overall prevalence of diabetes was 15.5% (95% CI 12.2-18.7%) in women and 20.1% (15.0-25.2%) in men (P = 0.13). The prevalence of previously diagnosed diabetes was similar to that of undiagnosed diabetes. Impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) were present in 16.8% (12.8-20.8%) of women and 29.7% (23.4-35.9%) of men (P = 0.0007). The combined rates of glucose intolerance (diabetes, IGT, and IFG) were 32.3% (27.8-36.7%) for women and 49.8% (43.1-56.4%) for men (P < 0.0001). Among younger adults, the prevalence in men was higher than that in women. As expected, subjects with diabetes or IGT/IFG were older and had greater BMI and waist-to-hip ratios than subjects with normal glucose tolerance.

CONCLUSIONS

The prevalence of diabetes and glucose intolerance is extremely high among adult Arab Americans in Michigan and represents a major clinical and public health problem. Community-based intervention programs to prevent and treat diabetes are urgently needed.