Genetic association studies of interleukin-13 receptor alpha1 subunit gene polymorphisms in asthma and atopy.

Interleukin (IL)-13 plays a central role in asthma pathogenesis by binding to the IL-13 receptor, which is a heterodimer composed of the IL-13 receptor alpha1 subunit (IL-13Ralpha1) and IL-4Ralpha. The genetic diversity at the IL-13Ralpha1 gene (IL13RA1) locus on chromosome Xq24 was characterised and the association of identified polymorphisms with asthma and atopy phenotypes examined. The promoter and coding region of IL13RA1 were screened for common genetic variants, and polymorphisms found were genotyped in a large cohort of 341 asthmatic Caucasian families (each containing at least two asthmatic siblings) and 182 nonasthmatic control subjects. Genetic association was determined using case-control and transmission disequilibrium test analyses. Two common polymorphisms were identified, a newly found thymidine (T) to guanine (G) transition of nucleotide -281 (-281T>G) single nucleotide polymorphism in the IL13RA1 promoter and the previously described 1365A>G variant in the IL13RA1 proximal 3' untranslated region. No significant association of either -281T>G or 1365A>G with risk of asthma or atopy phenotypes was found, apart from a suggestive association between the IL13RA1 -281T/1365A haplotype and raised total serum immunoglobulin E levels in adult female asthmatics. These findings indicate that the interleukin-13 receptor alpha1 subunit gene -281T>G and 1365A>G polymorphisms do not contribute to asthma susceptibility or severity, although the interleukin-13 receptor alpha1 subunit gene locus might be involved in the control of immunoglobulin E production.     

Disruption of the type 2 dopamine receptor gene causes a sodium-dependent increase in blood pressure in mice

BACKGROUND: Dopamine D(2) receptors (D(2)Rs) are expressed in the kidney. It has not been determined whether D(2)Rs are involved in the mechanism of sodium handling and blood pressure (BP) control. METHODS: The function of D(2)Rs was investigated in mice disrupted with D(2)R gene (D(2)KO mice). Six-week-old male D(2)KO mice and wild-type (WT) mice were fed high-salt (4% NaCl) or low-salt (0.01% NaCl) diets for 8 weeks. RESULTS: Before starting the metabolic diet, there were no significant differences in body weight, food consumption, and 24-h urine excretions of creatinine, sodium and potassium. The high-salt diet caused a significant elevation in systolic BP in D(2)KO mice but not in WT mice. Calculation of sodium and potassium balances revealed a significantly high level of sodium retention in D(2)KO mice placed on the high-salt diet. Twenty-four-hour urine norepinephrine excretions and heart rates, indicators of sympathetic activity, were not different in D(2)KO and WT mice on the high-salt diet. Administration of nemonapride, a specific D(2)-like receptor antagonist, to WT mice given 0.9% NaCl in drinking water caused suppression of urinary sodium excretion but had no effect in mice without salt loading. CONCLUSIONS: These results suggest that D(2) receptors promote sodium excretion during a period of high salt intake. A defect in this mechanism may result in sodium-dependent BP elevation.     

Angiotensin converting enzyme gene polymorphism predicts blood pressure response to angiotensin II receptor type 1 antagonist treatment in hypertensive patients

OBJECTIVES: To determine whether polymorphisms in the renin-angiotensin system can predict blood pressure-lowering response to antihypertensive treatment; more specifically, in response to treatment with irbesartan or atenolol. DESIGN AND METHODS: Eighty-six patients with hypertension were randomized to double-blind treatment with either the angiotensin II type 1 receptor antagonist irbesartan or the beta1 adrenergic receptor blocker atenolol and followed for 3 months. We analysed angiotensinogen T174M and M235T, angiotensin converting enzyme (ACE) I/D and angiotensin II type 1 receptor A1166C polymorphisms and related them to blood pressure reduction. RESULTS: The mean reductions in blood pressure were similar for both treatments. In the irbesartan group, individuals homozygous for the ACE gene I allele showed a greater reduction in diastolic blood pressure, exceeding those with the D allele (-18 +/- 11 SD versus -7 +/- 10 mmHg, P = 0.0096). This was not the case during treatment with atenolol, and the interaction term between type of treatment and ACE II genotype was significant (P = 0.0176). The angiotensinogen and angiotensin II type 1 receptor polymorhisms were not related to the response to treatment. CONCLUSIONS: ACE genotyping predicted the blood pressure-lowering response to antihypertensive treatment with irbesartan but not atenolol. Thus, specific genotypes might predict the response to specific antihypertensive treatment.     

Multilocus analyses of Renin-Angiotensin-aldosterone system gene variants on blood pressure at rest and during behavioral stress in young normotensive subjects

The renin-angiotensin-aldosterone system (RAAS) is a proteolytic cascade that regulates and maintains blood pressure (BP). This study aimed to explore the interactive and integrative effects of multiple RAAS polymorphisms on BP at rest and during behavioral stress in a normotensive population. A total of 920 young white and black twins (age: 12 to 30 years; 45% blacks) was subjected to three 10-minute stress tasks. Thirteen potential functional polymorphisms from 4 major RAAS genes were genotyped. We performed multilocus prediction allowing for genetic modification effects (gene-gene, gene-gender, gene-ethnicity, and gene-body mass index) using Multivariate Adaptive Regression Splines and generalized estimating equations. Single polymorphism analyses showed modest effects of M235T (angiotensinogen) and A-239T (angiotensin I-converting enzyme; P value range: 0.005 to 0.036), accounting for approximately 1% of the total variance of systolic BP at rest and during stress. Compared with this, the best multilocus models revealed multiple independent genetic modification effects (gene-gene, gene-gender, and gene-body mass index; P value range: 0.003 to 0.009), accounting for 2.5% and 7.3% of the total variance for systolic BP levels at rest and during stress, respectively. Our data support the hypothesis that multiple RAAS genetic modifications account for BP variation. We conclude that the RAAS genetic modifications may contribute more to the dynamic BP regulation in response to behavioral stress compared with the static BP value. In addition, we reported a gene-gene interaction between M235T (angiotensinogen) and A1159G (angiotensin I-converting enzyme) on stress systolic BP levels. We proposed a viable approach to test for the multiple genetic contributions to BP and hypertension.     

Vasodilatory effects of troglitazone improve blood pressure at rest and during mental stress in type 2 diabetes mellitus.

The present study examined the hemodynamic mechanisms of blood pressure (BP) lowering by troglitazone in patients with type 2 diabetes mellitus (DM) at rest and during a mental arithmetic test (MAT). Twenty-two patients with DM with normal to high-normal BP and 12 controls matched for age, gender, glucose tolerance, and BP were studied. DM subjects showed significantly higher systolic BP response during MAT than controls (157 versus 139 mm Hg; P<0.01). All 22 DM patients and 5 of 12 controls had systolic BP >140 mm Hg during MAT. Heart rate and diastolic BP were not significantly different between the 2 groups. The DM group was then randomized to receive troglitazone (n=10; 400 mg/d) or glyburide (n=12; 20 mg/d). MAT was repeated after 6 months of treatment. Both treatments reduced glucose equally (-1.7 mmol/L for troglitazone and -1.5 mmol/L for glyburide), but only troglitazone reduced insulin (-15 microU/mL; P<0.001) and C-peptide (-0.9 ng/mL; P<0.02) levels. Troglitazone significantly reduced BP at baseline (P<0.05) and systolic BP response to MAT (P<0.01), whereas glyburide did not affect BP at baseline or during MAT. Stroke volume and cardiac output did not change with either drug, but troglitazone decreased peripheral vascular resistance (-112 dyne. s. cm(-5); P<0.05). Improved insulin resistance rather than an improved glycemic control is associated with lower resting and stress BP values in patients with DM. A reduction in vascular resistance may be a primary hemodynamic mechanism of the manner in which troglitazone lowers BP. Insulin sensitizers may offer potential therapeutic advantage in subjects with DM with elevated BP.     

Effects of endothelial nitric oxide synthase, alpha-adducin, and other candidate gene polymorphisms on blood pressure response to hydrochlorothiazide

BACKGROUND: Pharmacogenetic discoveries may enable greater individualization of antihypertensive drug therapy. We investigated polymorphisms in the genes encoding endothelial nitric oxide synthase (Glu298-->Asp), alpha-adducin (Gly460-->Trp), the beta(1)-adrenoceptor (Arg389-->Gly), beta2-adrenoceptor (Arg16-->Gly), and lipoprotein lipase (Ser447-->Stop) for their potential influences on blood pressure (BP) response to a thiazide diuretic. METHODS: The sample consisted of 291 unrelated non-Hispanic African American adults (150 women and 141 men) and 294 unrelated non-Hispanic white adults (126 women and 168 men) who were between 30 and 59.9 years of age and who had essential hypertension. Previous antihypertensive drug therapy was withdrawn for at least 4 weeks, and subjects were then treated with hydrochlorothiazide (25 mg daily) for 4 weeks to determine BP response. RESULTS: The covariates of ethnicity, gender, age, and waist-to-hip ratio accounted for 26% of interindividual variation in systolic BP response and 11% of interindividual variation in diastolic BP response. After adjustment for covariates, the endothelial nitric oxide synthase Glu298-->Asp polymorphism made an additional statistically significant contribution to predicting diastolic BP response to hydrochlorothiazide, accounting for another 1% of interindividual variation in response (P =.034). In contrast, the other polymorphisms, including the alpha-adducin Gly460-->Trp polymorphism, made no statistically significant contributions to prediction of BP response. CONCLUSIONS: Although we reject the null hypothesis of no genetic effects on BP response to hydrochlorothiazide, the influence of variation at single sites is likely to be small. More extensive characterization of genetic variation is required for pharmacogenetic approaches to become clinically useful in tailoring antihypertensive drug therapy for individual patients.     

Racial differences in endothelin-1 at rest and in response to acute stress in adolescent males

Blacks exhibit greater vasoconstriction-mediated blood pressure (BP) increases in response to stress than do whites. Endothelin-1 (ET-1), a potent vasoconstrictive peptide, has been proposed as having a role in racial differences in stress reactivity. We evaluated the hemodynamic and plasma ET-1 levels of 41 (23 whites, 18 blacks, mean age 18.6 years) normotensive adolescent males at rest and in response to a video game challenge and forehead cold stimulation. Measurements were performed at catheter insertion and before and immediately after the 2 stressors, which were separated by 20-minute rest periods. Blacks exhibited higher absolute levels of diastolic blood pressure, total peripheral resistance index, or both in response to catheter insertion and to the video game challenge and during recovery from video game challenge and cold stimulation (P<0. 05 for all). Blacks exhibited higher absolute levels of ET-1 at every evaluation point (P<0.05 for all) and greater increases in ET-1 in response to both stressors (ps<0.05). These findings suggest that altered endothelial function may be involved in racial differences in hemodynamic reactivity to stress and possibly in the development of essential hypertension.     

Regulation of blood pressure by the type 1A angiotensin II receptor gene.

The renin-angiotensin system plays a critical role in sodium and fluid homeostasis. Genetic or acquired alterations in the expression of components of this system are strongly implicated in the pathogenesis of hypertension. To specifically examine the physiological and genetic functions of the type 1A receptor for angiotensin II, we have disrupted the mouse gene encoding this receptor in embryonic stem cells by gene targeting. Agtr1A(-/-) mice were born in expected numbers, and the histomorphology of their kidneys, heart, and vasculature was normal. AT1 receptor-specific angiotensin II binding was not detected in the kidneys of homozygous Agtr1A(-/-) mutant animals, and Agtr1A(+/-) heterozygotes exhibited a reduction in renal AT1 receptor-specific binding to approximately 50% of wild-type [Agtr1A(+/+)] levels. Pressor responses to infused angiotensin II were virtually absent in Agtr1A(-/-) mice and were qualitatively altered in Agtr1A(+/-) heterozygotes. Compared with wild-type controls, systolic blood pressure measured by tail cuff sphygmomanometer was reduced by 12 mmHg (1 mmHg = 133 Pa) in Agtr1A(+/-) mice and by 24 mmHg in Agtr1A(-/-) mice. Similar differences in blood pressure between the groups were seen when intraarterial pressures were measured by carotid cannulation. These studies demonstrate that type 1A angiotensin II receptor function is required for vascular and hemodynamic responses to angiotensin II and that altered expression of the Agtr1A gene has marked effects on blood pressures.     

Beta1-adrenergic receptor gene polymorphisms and response to beta1-adrenergic receptor blockade in patients with essential hypertension

BACKGROUND: Studies suggest that the Ser49Gly and Arg389Gly polymorphisms in the beta1-adrenergic receptor might be of functional importance for the cardiovascular system. Both have been associated with altered receptor activity in vitro, and with hypertension and cardiac failure in vivo. HYPOTHESIS: The aim of this study was to test whether these polymorphisms were associated with the change in heart rate or blood pressure in patients with essential hypertension and left ventricular (LV) hypertrophy treated with the beta1-adrenergic receptor blocker atenolol. METHODS: Blood pressure and heart rate were measured in 101 hypertensive patients with echocardiographically verified LV hypertrophy, randomized in a double-blind study to treatment with either the beta1-adrenergic receptor blocker atenolol or the angiotensin II type I receptor antagonist irbesartan. Changes in blood pressure and heart rate were evaluated after 12 weeks. Beta1-adrenergic receptor genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism. RESULTS: We found no significant associations between the changes in the measured variables and either of the two polymorphisms. However, carriers of the 49Gly allele showed a tendency toward a greater reduction in heart rate compared with patients with the Ser/Ser49 genotype (p = 0.06). CONCLUSIONS: The Ser49Gly and Arg389Gly beta1-adrenergic receptor polymorphisms do not seem to exert a major effect on the changes in heart rate and blood pressure during 12 weeks of treatment with atenolol in patients with essential hypertension and LV hypertrophy.     

Interleukin 1alpha,interleukin 1beta and interleukin 1 receptor gene polymorphisms in psoriatic arthritis

OBJECTIVES: To investigate polymorphisms of interleukin (IL) 1alpha, IL-1beta and IL-1 receptor R1 genes in patients with psoriatic arthritis (PsA), their relationship to the age of onset of psoriasis and the pattern of joint involvement. METHODS: One hundred and forty well-characterized patients with PsA were studied. One hundred healthy controls were recruited from primary care. All were genotyped for single-nucleotide polymorphisms in the genes for IL-1alpha (position -889), IL-1beta (position +3953) and IL-1R1 (position +970). The frequencies of the respective variants were compared between patients and controls and in relation to age of onset of psoriasis, to clinical subsets of the disease and to the presence of erosions. RESULTS: All three polymorphisms were in Hardy-Weinberg equilibrium in both patients and controls. The frequency of IL-1alpha -889 CC homozygotes was significantly increased in PsA patients compared with normal controls [58 vs 40%, odds ratio (OR) 2.06, 95%, confidence interval (CI) 1.22-3.47]. The frequency of the IL-1alpha -889 C allele was significantly increased in PsA patients compared with controls (75 vs 65%, OR 1.65, 95% CI 1.11-2.45). In subset analysis there were no other significant differences in allelic frequencies for the IL-1alpha -889 C/T, IL-1beta +3953 C/T and IL-1R1 +970 C/T polymorphisms. CONCLUSIONS: The IL-1 gene complex may play a role in the development of PsA and/or psoriasis or act as a marker for other genes on chromosome 2q12 to 2q13.     

Predictability of blood pressure response to isometric stress

Isometric exercise causes transient systemic hypertension, but with individual differences. An attempt was made to delineate predictors of those differences by analyzing the blood pressure (BP) response in terms of variables readily measured in clinical practice. For each of 270 office patients, we determined blood pressure, heart rate (HR), electrocardiographic findings, and symptoms in response to maximal isometric and maximal dynamic exercise. For systolic BP response as the predicted measure, 4 predictor variables in combination, including age, sex, resting systolic BP, and maximal treadmill systolic BP, yielded 70% predictability. For diastolic BP, 5 predictors in combination, including handgrip strength, resting diastolic BP, treadmill HR, systolic BP, and diastolic BP, allowed 66% prediction. Not predictive of either were resting HR, abnormality of treadmill test, presence of heart disease, and certain other medical diagnoses.     

Angiotensin II type 1 receptor polymorphisms in the cardiovascular health study: relation to blood pressure,ethnicity, and cardiovascular events

BACKGROUND: The angiotensin II type 1 receptor A1166C polymorphism has been associated with increased risks of hypertension and myocardial infarction in several small studies. We examined the association between this polymorphism and new-onset hypertension, blood pressure (BP) control, and incident cardiovascular events in a large population-based cohort of older adults. METHODS: Eight hundred self-identified African Americans and 1,371 randomly selected white participants in the Cardiovascular Health Study were genotyped. The median duration of follow-up was 8.1 years. RESULTS: The A1166C polymorphism was not associated with new-onset hypertension, with BP control, or with incident cardiovascular events in the overall population. In white participants, the CC genotype was associated with higher baseline systolic BP and pulse pressure, compared to the AC or AA genotype. In whites with treated hypertension at baseline, compared to the AA genotype, the CC genotype was associated with increased risks of incident congestive heart failure (hazard ratio = 2.5, 95% confidence interval [CI] 1.3-4.9) and incident ischemic stroke (hazard ratio = 2.6, 95% CI 1.1-6.0). These associations were not observed among white participants without treated hypertension, but the interaction of genotype with treated hypertension on ischemic stroke and heart failure was only marginally significant. CONCLUSIONS: On the whole, in this large cohort of older adults, the A1166C polymorphism was not associated with BP control or incident cardiovascular events. The subgroup findings in treated hypertensives need to be confirmed in additional studies.     

Genetic variation at the human alpha2B-adrenergic receptor locus: role in blood pressure variation and yohimbine response

Exaggerated response to alpha2-adrenergic receptor (alpha2-AR) blockade by yohimbine in normotensive subjects is an intermediate phenotype that predicts increased risk for development of hypertension. Here, we assessed the 3 alpha2-AR loci (alpha2A, alpha2B, alpha2C) as candidate genes for their influence on baseline and yohimbine-mediated increase in mean arterial pressure. Because initial results with 173 individuals implicated a possible association of yohimbine response with genetic variation at a site in the alpha2B-AR gene, but not at sites in the other 2 alpha2-AR, we sequenced the alpha2B-AR gene (4.4 kb, including 1.2 kb upstream and 1.9 kb distal to the coding sequence) in those subjects and an additional 81 individuals to search for other alpha2B-AR variants. We identified 25 polymorphisms, of which 14 are previously unreported, and 2 major haplotypes that differ by the presence/absence of a 9-bp in-frame deletion that encodes Glu301 to Glu303. Frequency differences in haplotypes were observed between blacks and whites but did not predict response to yohimbine. Genotyping of 2 additional white cohorts, including 1269 individuals with extremes in blood pressure selected from >50,000 subjects, also failed to reveal an association of the 2 major alpha2B-AR haplotypes with differences in blood pressure. Thus, despite considerable polymorphism in alpha2-AR genes, such variation is not a major determinant of variability in yohimbine response and by inference, in susceptibility to essential hypertension.     

Professional stress and blood pressure reactivity to stress do not predict blood pressure at 5 years

High job strain has been reported to be associated with higher blood pressure. Job strain could lead to hypertension if individual perception of stress or cardiovascular reactivity to stress are high. We report the results of the first five-year follow up study, which aimed to assess the respective influences of perception of professional strain and cardiovascular reactivity to a mental stress test on BP. A cohort of 292 healthy subjects (mean +/- SEM, 38 +/- 1 years) was followed for progression to hypertension outcome which was defined as an increase in SBP or DBP higher than 7 mmHg or a DBP higher than 95 mmHg during the follow-up. The high strain (HS) group representing 20.9% of the subjects was compared with the remaining subjects (NHS). Similarly the 20.9% subjects with the highest BP stress reactivity (HR) were compared with the remaining subjects (NHR). The Kaplan-Meier survival estimates revealed that neither high job strain, nor high stress reactivity, increased incidence of progression to hypertension. Age, alcohol, salt diet, BMI, and occupation did not interfere with our results. In conclusion, high stress cardiovascular reactivity and high job strain do not appear to be major risk markers for future high BP in healthy young adults. Stress could be associated with high BP at a short term and could explain high blood pressure in a long run only in stress-sensible subjects.     

Hemodynamic and central blood pressure differences between carvedilol and valsartan added to lisinopril at rest and during exercise stress

There is little information about the hemodynamic and exercise-response implications of renin-angiotensin system blocker combinations. After a 3-week lisinopril (L; 40 mg/day) run-in, carvedilol (C; 20 then 40 mg/day) or valsartan (V; 160 then 320 mg/day) was added to L for 4 weeks each in a forced-titration, random order-entry crossover study in 30 subjects. Arterial tonometry (central pressures and time-tension index, TTI); impedance cardiography (steady-state hemodynamics), and ultrasound (carotid flow) were performed at rest and during supine bicycle exercise at 30 and 60 watts. At rest, both V and C lowered TTI similarly (7% to 9%, P = .05 compared with L, in part because they lowered blood pressure (3 to 7/3 to 4 mm Hg). V lowered central systolic pressure, augmentation pressure (AP), and systemic vascular resistance (SVR, all P < .02); C lowered heart rate but not central systolic pressure or SVR. During exercise, V persistently lowered central systolic pressure, AP, and SVR, whereas C did not. Neither drug affected exercise responses or carotid blood flow. Adding V or C to an angiotensin-converting enzyme inhibitor reduced cardiac workload by different mechanisms: vasodilation and reduced central blood pressure with V and lower heart rate with C.     

Modulation of blood pressure and obesity with the dopamine D2 receptor gene TaqI polymorphism

Pharmacological data suggest that obesity and blood pressure (BP) may be modulated through the dopamine D2 receptor (DD2R), which may represent an underlying mechanism that links these conditions. A TAQ:I polymorphism near the DD2R gene has been associated with indices of obesity in white populations. We compared anthropometric and fasting plasma biochemical parameters between 209 nondiabetic hypertensive and 174 gender-matched normotensive Chinese subjects. The hypertensives had increased dyslipidemia, increased fasting plasma glucose concentrations, and a greater degree of obesity. The A1 and A2 alleles of the DD2R gene TAQ:I polymorphism were identified with a polymerase chain reaction-based restriction fragment length polymorphism protocol. The A1 allele frequency was decreased in the hypertensives (42.0%) compared with the control subjects (52.0%, P=0.006), and genotype frequencies were different (P=0.05) between the 2 groups. In the combined population (n=383), systolic, diastolic, and mean arterial BPs were 6, 5, and 6 mm Hg lower, respectively, in subjects with the A1A1 genotype relative to the A2A2 genotype (all P<0.05), whereas skinfold thickness was increased at the iliac (P<0.001) and triceps (P<0.03) sites but not at the biceps or subscapular sites. Furthermore, this DD2R gene polymorphism was shown to be a significant independent predictor of diastolic BP and iliac and triceps skinfold thicknesses (all P<0.03). These contrasting associations of the DD2R TAQ:I polymorphism A1 allele with lower BP but increased markers of "gynoidal" or peripheral subcutaneous obesity (iliac and triceps skinfold thicknesses) in our Chinese population may provide some insight into the underlying relationship between BP and body fat distribution, but the exact nature of this link remains to be determined.     

Influence of vitamin D receptor gene polymorphisms and 25-hydroxyvitamin D on blood pressure in apparently healthy subjects

BACKGROUND: There are no studies that relate BsmI polymorphism of the vitamin D receptor (VDR) gene and with vitamin D to blood pressure (BP). OBJECTIVE: To analyze if this polymorphism and 25-hydroxyvitamin D levels (25OHD3) influence BP in a population of healthy subjects. DESIGN: Transversal study on healthy population. Stepwise multiple regression analysis was performed to assess the association of BP with several clinical and biochemical data. SETTING: Industrial employees, blood donors, and army cadets from Lleida, Spain were recruited in October 2001. INDIVIDUALS: A total of 590 apparently healthy subjects (260 males and 330 females). MEASUREMENTS: Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were determined as the mean of three measurements. We also included age, gender, body mass index (BMI), serum levels of creatinine, calcium, phosphorus, intact parathyroid hormone (by two-site chemiluminometric assay), 25-hydroxyvitamin D (by radioimmunoassay) and BsmI genotype. RESULTS: Since gender was strongly associated with both SBP and DBP, a separate analysis was performed for men and women. In males, SBP was associated with BMI, 25OHD3 (beta: 0.37, P < 0.000) and genotype (beta: -4.1, P < 0.001); and DBP with 25OHD3 (beta: 0.19, P < 0.008) and age. SBP was higher in men with bb genotype than in the other genotypes (P < 0.006). Moreover, there was a statistically significant positive correlation between 25OHD3 and both SBP (r: 0.53, P < 0.002) and DBP (r: 0.48, P < 0.005) in men with genotype BB. In women, neither 25OHD3 nor genotype were associated with BP levels. CONCLUSIONS: BsmI polymorphism of the VDR gene influences BP in healthy men. A positive relationship between serum 25-hydroxyvitamin D levels and BP is present only in men with the BB genotype.     

Job strain, blood pressure and response to uncontrollable stress

OBJECTIVE: The association between cardiovascular disease risk and job strain (high-demand, low-control work) may be mediated by heightened physiological stress responsivity. We hypothesized that high levels of job strain lead to increased cardiovascular responses to uncontrollable but not controllable stressors. Associations between job strain and blood pressure reductions after the working day (unwinding) were also assessed. DESIGN: Assessment of cardiovascular responses to standardized behavioral tasks, and ambulatory monitoring of blood pressure and heart rate during a working day and evening. PARTICIPANTS: We studied 162 school teachers (60 men, 102 women) selected from a larger survey as experiencing high or low job strain. METHODS: Blood pressure, heart rate and electrodermal responses to an externally paced (uncontrollable) task and a self-paced (controllable) task were assessed. Blood pressure was monitored using ambulatory apparatus from 0900 to 2230 h on a working day. RESULTS: The groups of subjects with high and low job strain did not differ in demographic factors, body mass or resting cardiovascular activity. Blood pressure reactions to the uncontrollable task were greater in high than low job-strain groups, but responses to the controllable task were not significantly different between groups. Systolic and diastolic blood pressure did not differ between groups over the working day, but decreased to a greater extent in the evening in subjects with low job strain. CONCLUSIONS: Job strain is associated with a heightened blood pressure response to uncontrollable but not controllable tasks. The failure of subjects with high job strain to show reduced blood pressure in the evening may be a manifestation of chronic allostatic load.