Age, body mass index, race and other determinants of steroid hormone variability: the HERITAGE Family Study

OBJECTIVE AND METHODS

To investigate from the HERITAGE Family Study database, 13 steroid hormones (androstane-3alpha, 17beta-diol glucuronide, androsterone glucuronide, cortisol, dehydroepiandrosterone (DHEA), DHEA ester (DHEAE), DHEA sulfate (DHEAS), dihydrotestosterone (DHT), estradiol, 17-hydroxyprogesterone, progesterone, pregnenolone ester, sex hormone binding globulin (SHBG) and testosterone in each sex for their relationships with age, body mass index (BMI), race and key lifestyle variables. Sample sizes varied from 676 to 750 per hormone. Incremental regression methods were used to examine the contributions of the variables to steroid hormone variability.

RESULTS

Age was a major predictor for most steroid hormones. The greatest contribution of age was a negative relationship with DHEAS (R(2)=0.39). BMI was also associated with the variability of several steroid hormones, being the most important predictor of SHBG (R(2)=0.20) and of testosterone (R(2)=0.12) concentrations. When age and BMI were included, race still contributed significantly to the variations in cortisol (R(2)=0.02 for men and 0.04 for women), DHT (R(2)=0.02 for men and 0.03 for women), and progesterone (R(2)=0.03 for women). Nevertheless, race appeared to be less important than age and BMI. In addition, lifestyle indicators (food and nutrient intakes, smoking and physical activity) influenced steroid hormone variability. Their contributions, however, were minor in most cases once age, BMI and race had been taken into account.

CONCLUSIONS

We conclude that age was the most important factor, followed by BMI, race and lifestyle factors in explaining steroid hormone variability.

Lack of association between polymorphisms of catalase, copper-zinc superoxide dismutase (SOD), extracellular SOD and endothelial nitric oxide synthase genes and macroangiopathy in patients with type 2 diabetes mellitus

OBJECTIVES

The association between the polymorphisms of three different antioxidative enzyme - catalase, copper-zinc superoxide dismutase (Cu/ Zn-SOD) and extracellular superoxide dismutase (EC-SOD) - genes and macroangiopathy was examined in patients with type 2 diabetes mellitus. The prevalence of the missense Glu298Asp variant of the endothelial nitric oxide synthase (eNOS) gene and its association with macroangiopathy were also determined.

DESIGN

Cross-sectional study. Setting. District around Oulu University Hospital, North Finland. Subjects and methods. A total of 239 patients with type 2 diabetes mellitus and 245 control subjects were screened. Genotypes were determined by polymerase chain reaction (PCR) technique. The diagnosis of coronary heart disease (CHD) was based on clinical and ECG criteria. The prevalences of cerebrovascular (CVD) and peripheral vascular diseases (PVD) were assessed on the basis of clinical criteria. Laboratory analyses were carried out in the hospital laboratory.

RESULTS

No differences in the genotype distributions and allele frequencies of the antioxidative enzymes were found between type 2 diabetes mellitus patients and controls. The eNOS genotypes and allele frequencies were also similar in the diabetic patients and controls being close to that reported earlier in the British population. None of the polymorphisms were associated with macro- or microangiopathy or hypertension. However, male diabetic patients with eNOS Asp298Asp genotype had higher plasma very-low density lipoprotein (VLDL) cholesterol and VLDL-triglyceride concentrations than those with the genotypes Glu298Glu or Glu298Asp (P < 0.01 for trend).

CONCLUSIONS

The polymorphism of catalase, Cu/Zn SOD and EC-SOD genes were not related to cardiovascular disease in type 2 diabetes mellitus patients. The eNOS Glu298Asp variant was associated with plasma VLDL-containing lipoproteins but not with macroangiopathy in diabetic male patients. The findings do not support the notion that the polymorphisms of the key antioxidative enzymes could be amongst the factors that explain the high prevalence of macroangiopathy in patients with type 2 diabetes mellitus.

Clustering of metabolic abnormalities in obese individuals: the role of genetic factors

The objective of this paper is to review the current evidence in support of genetic factors underlying the clustering of components of the metabolic syndrome in obese individuals. It has become clear that individual features of the metabolic syndrome are partially determined by familial factors some of which are unique to a given component and others that are shared among several features. A few candidate genes, encoding proteins of glucose, insulin and lipid metabolism, lipolytic cascade, fatty acid intestinal absorption, glucocorticoid metabolism, haemostasis and blood pressure, have been associated with a clustering of metabolic abnormalities, although the functional significance of these associations remains to be established. Furthermore, genetic polymorphisms, such as those detected at several lipoprotein metabolism loci, can modulate the relationships between different components of the metabolic syndrome. An overfeeding study conducted on identical twins has demonstrated that genetic factors play an important role in the responsiveness to changing energy balance conditions. Leptin receptor, beta2 adrenergic receptor and glucocorticoid receptor gene polymorphisms have been associated with an augmented clustering of metabolic abnormalities in response to overfeeding. Gene-gene interaction effects between markers of the alpha2A, beta2 and beta3 adrenergic receptor genes on components of the metabolic syndrome have been described. Genetic factors also seem to modify the responsiveness of metabolic syndrome features to endurance training. A growing understanding of the genetic architecture of the metabolic syndrome may help in the prevention of this condition. The reduction of excess body fat, the most common clinical feature among the cluster of metabolic abnormalities, should be the focus of the prevention and treatment of the metabolic syndrome.

Interactions among the glucocorticoid receptor, lipoprotein lipase, and adrenergic receptor genes and plasma insulin and lipid levels in the Quebec Family Study

The aim of the study was to investigate the possible interactions among the glucocorticoid receptor (GRL), lipoprotein lipase (LPL), and adrenergic receptor (ADR) genes on plasma insulin and lipid levels. The study was cross-sectional and based on 742 individuals from phase 2 of the Quebec Family Study (QFS) cohort. Gene markers were identified by Southern blot analysis or polymerase chain reaction (PCR). Plasma glucose and insulin in the fasted state and during an oral glucose tolerance test (OGTT) were determined and insulin and glucose areas were computed. Triglyceride (TG) and cholesterol concentrations in plasma and lipoprotein fractions were determined enzymatically. The results show that GRL and LPL variants had independent effects on plasma high-density lipoprotein cholesterol (HDL-C) and two beta2-ADR variants were related to total cholesterol concentrations. The alpha2-ADR gene Dral polymorphism was the only variant that had an independent effect on the plasma insulin area. Gene-gene interaction effects were found between GRL and alpha2-ADR genes for low-density lipoprotein cholesterol ([LDL-C] P = .013) and between GRL and LPL genes for HDL-C (P = .045). Higher-order interaction effects involving GRL, LPL, and ADR markers were observed for the plasma insulin area (P = .001 to .025) but not the glucose area. After correction for multiple tests, the findings remained essentially unchanged for the insulin area but became nonsignificant for the lipid phenotypes. In conclusion, multiple interactions among GRL, LPL, and ADR gene markers contribute to insulin metabolism and perhaps to lipid levels, while no significant effect is found for each gene separately. The LPL locus appears to determine the pattern of interactions with ADR and GRL loci. These results suggest that gene-gene interaction effects could play a role in the etiology of risk factors for common chronic diseases.

Leptin receptor Gln223Arg variant is associated with a cluster of metabolic abnormalities in response to long-term overfeeding

OBJECTIVES

The role of the leptin receptor (LEPR) gene Gln223Arg polymorphism on the metabolic and body composition changes in response to overfeeding was studied.

SUBJECTS

Twelve pairs of male monozygotic twins ate a 4.2 MJ day-1 energy surplus, 6 days week-1, during a period of 100 days.

RESULTS

Overfeeding induced a significantly greater increase in glucose (P = 0.001 for percentage change) and insulin (P = 0.038) areas under the curve during oral glucose tolerance tests (OGTTs) in the GlnGln (n = 10) than in the GlnArg/ArgArg (n = 14) subjects. In addition, the GlnGln genotype was associated with a greater increase in plasma levels of leptin (P = 0.037) and total triglycerides (P = 0.003), as well as a greater decrease in high-density lipoprotein cholesterol (P = 0.010), than for the combined GlnArg/ArgArg genotypes. Body composition changes were not different between the genotypes.

CONCLUSIONS

We conclude that the GlnGln subjects of the LEPR gene polymorphism are more susceptible to metabolic abnormalities when they are exposed to long-term positive energy balance. These findings provide new information on the genetic basis of individual differences in response to chronically elevated food intake.

Polymorphisms of the beta2-adrenergic receptor gene (ADRB2) in relation to cardiovascular risk factors in men

OBJECTIVE

To investigate the effect of polymorphisms in codon 16 (Arg16Gly) and codon 27 (Gln27Glu) of the beta2-adrenergic receptor gene (ADRB2) on anthropometric, endocrine, metabolic and haemodynamic variables.

DESIGN

A cross-sectional study.

SUBJECTS

A subgroup of 284 Swedish men from a population sample of 1040 at the age of 51 years.

MAIN OUTCOME MEASURES

Genotype examination of ADRB2 polymorphisms in codon 16 and codon 27 with polymerase chain reaction and restriction fragment length polymorphism. Anthropometric measurements included body mass index, waist-to-hip ratio and abdominal sagittal diameter. Endocrine measurements included blood levels of testosterone, insulin-like growth factor I, and leptin plus salivary cortisol. Overnight fasting values of serum insulin, blood glucose, triglycerides, total, low and high density lipoprotein cholesterol, as well as blood pressure and resting heart rate, were also determined.

RESULTS

Polymorphisms were frequent in both codon 16 and codon 27. The Arg16Gly genotype showed significant relationships to elevated central distribution of body fat and to systolic blood pressure, whilst the Glu27Glu genotype was associated with elevated leptin and triglyceride levels but not to other measurements, including obesity variables.

CONCLUSIONS

We conclude that only a few cardiovascular risk factors are associated with DNA sequence variation in the ADRB2 in Swedish men.

Interactions among the alpha2-, beta2-, and beta3-adrenergic receptor genes and obesity-related phenotypes in the Quebec Family Study

The gene-gene interactions between markers in the alpha2-, beta2-, and beta3-adrenergic receptor (ADR) genes and obesity-related phenotypes were studied in the Quebec Family Study (QFS) cohort. The prevalence of the Arg allele of the Arg16Gly polymorphism in the beta2-ADR gene was higher (49%) in males with a body mass index (BMI) of 35 kg/m2 or higher versus those with a BMI less than 35 kg/m2 (33%; P = .010). The beta2-ADR gene Arg16Gly and Gln27Glu polymorphisms were associated with plasma total and low-density lipoprotein (LDL) cholesterol concentrations. In addition, the homozygotes for the 6.3-kb allele of DraI polymorphism in the alpha2-ADR gene had the lowest mean abdominal subcutaneous fat area (P = .012) and total fat area (P = .003), as well as insulin area, under the curve during an oral glucose tolerance test ([OGTT] P = .004). Several ADR gene-gene interaction effects on abdominal fat distribution and plasma lipids were detected. First, significant interactions between alpha2- and beta3-ADR genes were observed on total (P = .015) and subcutaneous (P = .004) abdominal fat. Second, interaction effects between alpha2- and beta2-ADR gene variants influenced total, high-density lipoprotein (HDL), and LDL cholesterol concentrations. Finally, there were interactions between markers within the beta2-ADR gene affecting plasma triglyceride concentrations and subcutaneous abdominal fat. From these results, we conclude that polymorphisms in the ADR genes contribute to body fat and plasma lipid variability in men. Gene-gene interactions among the ADR genes contribute to the phenotypic variability in abdominal obesity and plasma lipid and lipoprotein, but not in visceral fat levels.

Improved metabolic control in patients with non-insulin-dependent diabetes mellitus is associated with a slower accumulation of glycation products in collagen

Twenty-one patients with non-insulin-dependent diabetes in poor metabolic control were subjected to intensified therapy, in most cases with insulin, to investigate whether it is possible to slow down the accumulation of advanced glycosylation end products of collagen by improving glycaemic control. Fasting and mean daily blood glucose, serum fructosamine and glycohaemoglobin levels, as well as glycation of collagen were measured before and after 1.5 years of intensified therapy. All these parameters except for fructosamine correlated significantly with fasting blood glucose and glycohaemoglobin when measured before the insulin therapy was started, when the patients had had poor but stable metabolic control for a long period of time. After 1.5 years of intensified therapy the level of glycation of collagen did not significantly correlate with the fasting blood glucose or glycohaemoglobin levels, suggesting that the non-enzymatic glycosylation of collagen reflects a longer period of metabolic control of diabetes than the glycohaemoglobin level. Intensified treatment improved previously poor metabolic control in patients with non-insulin-dependent diabetes, and this improvement was reflected in a decrease in fasting and mean daily blood glucose levels, serum fructosamine and glycohaemoglobin concentrations, and in the level of early products of glycation of collagen. The average content of advanced glycosylation end products of collagen, assayed in terms of collagen-linked fluorescence did not decrease. However, they accumulated more slowly in the patient tercile with the greatest decrease in the level of fasting blood glucose than in the tercile with the smallest decrease, and even a decrease in fluorescence was observed in the patients with the greatest improvement in the metabolic control.(ABSTRACT TRUNCATED AT 250 WORDS)

Insertion/deletion polymorphism in the angiotensin-converting enzyme gene associated with macroangiopathy and blood pressure in patients with non-insulin-dependent diabetes mellitus

In the search for new risk factors for diabetic macroangiopathy the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene was studied in 237 consecutive patients (125 men and 112 women) with non-insulin-dependent diabetes. The female population showed an excess of ischemic electrocardiographic changes or definite myocardial infarctions in the patients homozygous for the deletion [D/D; odds ratio (OR) 2.8; 95% confidence interval (CI) 1.4-5.3] and in the insertion/deletion heterozygotes (I/D; OR 1.8; CI 1.1-3.1) compared with the patients homozygous for the insertion (I/I). In the total series coronary heart disease, cerebrovascular disease, and claudication were more often observed in the patients with I/D (OR 1.5; CI 1.0-2.2) or the D/D genotype patients (OR 1.7; CI 1.1-2.6) than in those with the genotype I/I. The systolic blood pressure was lower in patients with genotype I/I (138 +/- 19 mmHg) than in those with the genotype I/D (149 +/- 22 mmHg) or D/D (150 +/- 21 mmHg; P < 0.02). The prevalence of hypertension and the median urinary albumin excretion rate also tended to be lowest in the I/I genotype patients. Multiple logistic analysis revealed that in women the angiotensin-converting enzyme D/D genotype is independently associated with coronary heart disease. Our findings suggest that variation at the angiotensin-converting enzyme gene locus is one of the factors involved in the predisposition of diabetic patients to the development of arterial disease and hypertension.

DNA polymorphisms at the lipoprotein lipase gene are associated with macroangiopathy in type 2 (non-insulin-dependent) diabetes mellitus

We studied the effect of variation at the lipoprotein lipase (LPL) gene locus on the susceptibility of individuals with Type 2 diabetes mellitus to atherosclerotic vascular disease in a population of 126 male and 114 female patients. The prevalence of any evidence of coronary heart disease (CHD) (presence of ischaemic ECG changes or definite myocardial infarction) was low in the patients who were homozygous for the presence of the PvuII restriction site (genotype 2-2) (40.9%) compared with those who were heterozygous (genotype 1-2) (57.9%; P = 0.05) or homozygous for the absence of it (genotype 1-1) (61.9%; P < 0.04). In men, a clear gene dosage effect on CHD was seen, the genotype 2-2 patients having the lowest (39.1%), the 1-2 patients an intermediate (49.3%) and the 1-1 patients the highest (61.1%) frequency of coronary disease. Patients with the genotype 2-2 of the HindIII polymorphism (absence of the restriction site) had the highest prevalence of any evidence of CHD (90.0%) compared with the genotype 1-2 (heterozygotes for the presence of the restriction site) (55.4%) or 1-1 (presence of the restriction site) (54.6%; P < 0.03). Stepwise discriminant analysis revealed that in the whole diabetic population the PvuII genotype of the LPL gene was independently and significantly associated with CHD but its effect decreased when the plasma lipids were taken into account. Overall, this study demonstrates the role of the PvuII polymorphism in the LPL gene to modulate the risk for diabetic macroangiopathy in patients with Type 2 diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA polymorphisms at the locus for human cholesteryl ester transfer protein (CETP) are associated with macro- and microangiopathy in non-insulin-dependent diabetes mellitus

The effect of variation at the cholesteryl ester transfer protein (CETP) gene locus and in the apolipoprotein (apo) AI-CIII-AIV gene cluster on the susceptibility of individuals with non-insulin-dependent diabetes mellitus (NIDDM) to atherosclerotic vascular disease was studied in 136 male and 122 female patients with NIDDM. The prevalence of myocardial infarction was high (38%) in patients with the EcoNI genotype 2-2 of the CETP gene locus (= 2-2; subjects homozygous for the absence of the restriction site) compared with patients with the genotype 1-1 (= 1-1; subjects homozygous for the presence of the restriction site) (18%, p < 0.02). The prevalence of any evidence of coronary heart disease (CHD) (presence of ischaemic ECG changes or definite myocardial infarction) was high in 2-2 (73%) compared with the genotype 1-2 (= 1-2; heterozygous for the presence of the restriction site) (52%, p < 0.02) and genotype 1-1 (p = 0.06). CHD was more prevalent in men with 2-2 (70%) than in those with 1-1 (42%, p < 0.05), but in women no significant differences were found in the prevalences of CHD between the EcoNI genotypes. Neuropathy was more often present in the patients with 2-2 (31%) than in those with 1-1 (12%, p < 0.02) or 1-2 (14%, p < 0.01). Plasma total cholesterol and total- and VLDL-triglycerides were higher in women with the EcoNI genotype 1-1 than in those with the genotype 1-2. In men no significant differences in plasma lipids were found. In addition, the prevalence of cerebrovascular disease was high (21%) in the patients with the genotype 1-1 of the TaqIB polymorphism compared with the genotype 2-2 (6%, p < 0.02). None of the alleles defined by four polymorphisms in the apo AI-CIII-AIV gene region were associated with an increased risk for macroangiopathy. The PstI polymorphism had an effect on plasma triglyceride levels. At the CETP locus one pair of loci (TaqIB and EcoNI) and three pairs of loci at the apo AI-CIII-AIV gene cluster (SacI and MspI, SacI and PvuII and MspI and PvuII) showed significant allelic association. In conclusion, the variation of CETP locus modulates the risk for diabetic complications in patients with NIDDM and the effect seems to be different between men and women. In contrast, the AI-CIII-AIV gene cluster polymorphisms seem not to be related to the risk of CHD in NIDDM.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of early administration of enalapril on radionuclide left ventricular ejection fraction and plasma N-terminal atrial natriuretic peptide after acute myocardial infarction

The effects of enalapril therapy on radionuclide ejection fraction and plasma N-terminal atrial natriuretic peptide were investigated in a randomized, double-blind, placebo-controlled study of 52 patients with acute myocardial infarction. The medication was begun intravenously within 24 hours of the onset of symptoms. At discharge and the end point of 6 months, the radiographic size of the heart was significantly smaller in patients receiving (n = 28) than in those not receiving (n = 24) enalapril therapy (p < 0.03 vs < 0.01). However, left ventricular ejection fraction decreased simultaneously from 50 +/- 10% to 47 +/- 11% in patients treated with enalapril, whereas it increased from 48 +/- 13% to 50 +/- 14% in control patients (p < 0.05 for the difference of the changes). The decrease in ejection fraction was most marked in the infarct-related region of the left ventricle (p < 0.01). During the in-hospital period, plasma N-terminal atrial natriuretic peptide was decreased in patients treated with enalapril, whereas it was increased in those treated with placebo with complicated acute myocardial infarction (p < 0.05). During the following 6 months, the differences remained insignificant. Early administration of enalapril significantly attenuated heart enlargement after myocardial infarction and probably improved hemodynamics during the acute phase of complicated infarction. The decrease in ejection fraction during recovery indicates an impairment of systolic function. The decrease in infarct-related regional ejection fraction suggests that the impairment may be due to poor healing of the infarction scar.

Apolipoprotein E phenotype is related to macro- and microangiopathy in patients with non-insulin-dependent diabetes mellitus

The role of apoliprotein E (apo E) in modulating the susceptibility of individuals with non-insulin-dependent diabetes mellitus (NIDDM) to atherosclerotic vascular disease was studied in 143 male and 128 female patients with NIDDM. The data show that the apolipoprotein phenotype E2 somehow protects from macrovascular complications in NIDDM both in men and women. E2 also tends to protect from microvascular complications. In contrast, apo E phenotypes E4/4 and E4/3 tend to increase the risk for macroangiopathy in NIDDM patients. The lower prevalence of macroangiopathy in the subjects with E2 was associated with lower plasma total and LDL cholesterol concentrations and low plasma lipoprotein(a) levels. Overall, this study demonstrates the role of the apo E phenotype to modulate the risk for diabetic complications in patients with NIDDM. The confirmation of the association of apo E polymorphism with diabetic complications warrants, however, long-term follow-up studies.

Apolipoprotein B gene DNA polymorphisms are associated with macro- and microangiopathy in non-insulin-dependent diabetes mellitus

The relationship between diabetic macroangiopathy or microangiopathy and apolipoprotein B (apoB) polymorphism was studied in 139 male and 129 female patients with non-insulin-dependent diabetes (NIDDM) mellitus, comprising consecutive patients with poor diabetic control (HBA1 13.2% +/- 2.7 (SD)) referred to our hospital. Plasma cholesterol and triglyceride concentrations were higher in the patients who were homozygous for the X2 allele (presence of XbaI cleavage site). Patients with the X1 allele (absence of XbaI cleavage site) tended to have a higher frequency of macroangiopathy, although the differences were not statistically significant. There was no difference in the prevalence of microangiopathy between the groups. In subjects with only an R1 allele (= R+; homozygous for the presence of EcoRI cleavage site) the prevalence of coronary heart disease (CHD) was observed to be high (61.9%) as compared to the subjects possessing an R2 allele (= R-; homozygous or heterozygous for the absence of the EcoRI cleavage site) (46.7%; p < 0.02). When the polymorphisms XbaI (subjects homozygous for the absence of the cutting site = X+; subjects homozygous or heterozygous for the presence of the cutting site = X-) and EcoRI were combined, the prevalence of macroangiopathy was observed to be high in X+R+ (80.0%) as compared with X+R- (44.2%), X-R+ (56.8%) and X-R- (50.0%) (p < 0.03). The prevalence of macroangiopathy tended to be particularly high in patients with the apoprotein E4 allele (phenotype E4/4 or E4/3), combined with either X+ or R+.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein E phenotype is related to macro- and microangiopathy in patients with non-insulin-dependent diabetes mellitus

The role of apoliprotein E (apo E) in modulating the susceptibility of individuals with non-insulin-dependent diabetes mellitus (NIDDM) to atherosclerotic vascular disease was studied in 143 male and 128 female patients with NIDDM. The data show that the apolipoprotein phenotype E2 somehow protects from macrovascular complications in NIDDM both in men and women. E2 also tends to protect from microvascular complications. In contrast, apo E phenotypes E4/4 and E4/3 tend to increase the risk for macroangiopathy in NIDDM patients. The lower prevalence of macroangiopathy in the subjects with E2 was associated with lower plasma total and LDL cholesterol concentrations and low plasma lipoprotein(a) levels. Overall, this study demonstrates the role of the apo E phenotype to modulate the risk for diabetic complications in patients with NIDDM. The confirmation of the association of apo E polymorphism with diabetic complications warrants, however, long-term follow-up studies.