A1 beta-casein milk protein and other environmental pre-disposing factors for type 1 diabetes.

Globally type 1 diabetes incidence is increasing. It is widely accepted that the pathophysiology of type 1 diabetes is influenced by environmental factors in people with specific human leukocyte antigen haplotypes. We propose that a complex interplay between dietary triggers, permissive gut factors and potentially other influencing factors underpins disease progression. We present evidence that A1 ß-casein cows' milk protein is a primary causal trigger of type 1 diabetes in individuals with genetic risk factors. Permissive gut factors (for example, aberrant mucosal immunity), intervene by impacting the gut's environment and the mucosal barrier. Various influencing factors (for example, breastfeeding duration, exposure to other dietary triggers and vitamin D) modify the impact of triggers and permissive gut factors on disease. The power of the dominant trigger and permissive gut factors on disease is influenced by timing, magnitude and/or duration of exposure. Within this framework, removal of a dominant dietary trigger may profoundly affect type 1 diabetes incidence. We present epidemiological, animal-based, in vitro and theoretical evidence for A1 ß-casein and its ß-casomorphin-7 derivative as dominant causal triggers of type 1 diabetes. The effects of ordinary milk containing A1 and A2 ß-casein and milk containing only the A2 ß-casein warrant comparison in prospective trials.

CD39 overexpression does not attenuate renal fibrosis in the unilateral ureteric obstructive model of chronic kidney disease.

Chronic kidney disease has multiple etiologies, but its single, hallmark lesion is renal fibrosis. CD39 is a key purinergic enzyme in the hydrolysis of ATP and increased CD39 activity on regulatory T cells (Treg) is protective in adriamycin-induced renal fibrosis. We examined the effect of overexpression of human CD39 on the development of renal fibrosis in the unilateral ureteric obstructive (UUO) model, a model widely used to study the molecular and cellular factors involved in renal fibrosis. Mice overexpressing human CD39 (CD39Tg) and their wild-type (WT) littermates were subjected to UUO; renal histology and messenger RNA (mRNA) levels of adenosine receptors and markers of renal fibrosis were examined up to 14 days after UUO. There were no differences between CD39Tg mice and WT mice in the development of renal fibrosis at days 3, 7, and 14 of UUO. Relative mRNA expression of the adenosine A2A receptor and endothelin-1 were higher in CD39Tg than WT mice at day 7 post UUO, but there were no differences in markers of fibrosis. We conclude that human CD39 overexpression does not attenuate the development of renal fibrosis in the UUO model. The lack of protection by CD39 overexpression in the UUO model is multifactorial due to the different effects of adenosinergic receptors on the development of renal fibrosis.

Adenosine receptor expression in the development of renal fibrosis following ischemic injury.

Long-term renal allograft survival has not improved despite improvements in short term outcomes. Graft loss is characterized histologically by the development of interstitial fibrosis and tubular atrophy (IFTA). Mechanisms underlying the development of IFTA are multifactorial and include ischemia-reperfusion injury (IRI). Therapeutic options to reduce IFTA include management of immunologic causes, such as rejection, but despite these efforts IFTA can still occur and leads to the inexorable destruction of the transplanted kidney. The adenosine A2B receptor (A2BR) has recently been implicated in the development of renal fibrosis. We performed an observational study to examine the mRNA expression of the adenosine receptors after renal ischemia up to the development of renal fibrosis in a mouse model of unilateral IRI. A2BR was the only adenosine receptor that showed elevated expression following ischemia until the development of renal fibrosis 4 weeks after injury. At 2 weeks after ischemia, increased expression of the fibrotic markers transforming growth factor ß and Collagen-1α was observed. Expression of hypoxia inducible factor 1α and endothelin-1, which lie downstream of A2BR activation and have been recognized to promote renal fibrosis, were also significantly up-regulated at 2 weeks after ischemia. Expression of fibrotic markers returned to baseline by 4 weeks after ischemia, indicating resolution of injury with the concurrent development of renal fibrosis and reduced renal function. Our data suggest that A2BR may be a therapeutic target in reducing the development of renal fibrosis after ischemia.

Antioxidant network expression abrogates oxidative posttranslational modifications in mice.

Antioxidant enzymatic pathways form a critical network that detoxifies ROS in response to myocardial stress or injury. Genetic alteration of the expression levels of individual enzymes has yielded mixed results with regard to attenuating in vivo myocardial ischemia-reperfusion injury, an extreme oxidative stress. We hypothesized that overexpression of an antioxidant network (AON) composed of SOD1, SOD3, and glutathione peroxidase (GSHPx)-1 would reduce myocardial ischemia-reperfusion injury by limiting ROS-mediated lipid peroxidation and oxidative posttranslational modification (OPTM) of proteins. Both ex vivo and in vivo myocardial ischemia models were used to evaluate the effect of AON expression. After ischemia-reperfusion injury, infarct size was significantly reduced both ex vivo and in vivo, ROS formation, measured by dihydroethidium staining, was markedly decreased, ROS-mediated lipid peroxidation, measured by malondialdehyde production, was significantly limited, and OPTM of total myocardial proteins, including fatty acid-binding protein and sarco(endo)plasmic reticulum Ca(²+)-ATPase (SERCA)2a, was markedly reduced in AON mice, which overexpress SOD1, SOD3, and GSHPx-1, compared with wild-type mice. These data demonstrate that concomitant SOD1, SOD3, and GSHPX-1 expression confers marked protection against myocardial ischemia-reperfusion injury, reducing ROS, ROS-mediated lipid peroxidation, and OPTM of critical cardiac proteins, including cardiac fatty acid-binding protein and SERCA2a.

Expression of CD39 by human peripheral blood CD4+ CD25+ T cells denotes a regulatory memory phenotype.

We have shown that CD39 and CD73 are coexpressed on the surface of murine CD4+ Foxp3+ regulatory T cells (Treg) and generate extracellular adenosine, contributing to Treg immunosuppressive activity. We now describe that CD39, independently of CD73, is expressed by a subset of blood-derived human CD4+ CD25+ CD127lo Treg, defined by robust expression of Foxp3. A further distinct population of CD4+ CD39+ T lymphocytes can be identified, which do not express CD25 and FoxP3 and exhibit the memory effector cellular phenotype. Differential expression of CD25 and CD39 on circulating CD4+ T cells distinguishes between Treg and pathogenic cellular populations that secrete proinflammatory cytokines such as IFNγ and IL-17. These latter cell populations are increased, with a concomitant decrease in the CD4+ CD25+ CD39+ Tregs, in the peripheral blood of patients with renal allograft rejection. We conclude that the ectonucleotidase CD39 is a useful and dynamic lymphocytes surface marker that can be used to identify different peripheral blood T cell-populations to allow tracking of these in health and disease, as in renal allograft rejection.

Transgenic overexpression of CD39 protects against renal ischemia-reperfusion and transplant vascular injury.

The vascular ectonucleotidases CD39[ENTPD1 (ectonucleoside triphosphate diphosphohydrolase-1), EC 3.6.1.5] and CD73[EC 3.1.3.5] generate adenosine from extracellular nucleotides. CD39 activity is critical in determining the response to ischemia-reperfusion injury (IRI), and CD39 null mice exhibit heightened sensitivity to renal IRI. Adenosine has multiple mechanisms of action in the vasculature including direct endothelial protection, antiinflammatory and antithrombotic effects and is protective in several models of IRI. Mice transgenic for human CD39 (hCD39) have increased capacity to generate adenosine. We therefore hypothesized that hCD39 transgenic mice would be protected from renal IRI. The overexpression of hCD39 conferred protection in a model of warm renal IRI, with reduced histological injury, less apoptosis and preserved serum creatinine and urea levels. Benefit was abrogated by pretreatment with an adenosine A2A receptor antagonist. Adoptive transfer experiments showed that expression of hCD39 on either the vasculature or circulating cells mitigated IRI. Furthermore, hCD39 transgenic kidneys transplanted into syngeneic recipients after prolonged cold storage performed significantly better and exhibited less histological injury than wild-type control grafts. Thus, systemic or local strategies to promote adenosine generation and signaling may have beneficial effects on warm and cold renal IRI, with implications for therapeutic application in clinical renal transplantation.

Anti-inflammatory and anticoagulant effects of transgenic expression of human thrombomodulin in mice.

Thrombomodulin (TBM) is an important vascular anticoagulant that has species specific effects. When expressed as a transgene in pigs, human (h)TBM might abrogate thrombotic manifestations of acute vascular rejection (AVR) that occur when GalT-KO and/or complement regulator transgenic pig organs are transplanted to primates. hTBM transgenic mice were generated and characterized to determine whether this approach might show benefit without the development of deleterious hemorrhagic phenotypes. hTBM mice are viable and are not subject to spontaneous hemorrhage, although they have a prolonged bleeding time. They are resistant to intravenous collagen-induced pulmonary thromboembolism, stasis-induced venous thrombosis and pulmonary embolism. Cardiac grafts from hTBM mice to rats treated with cyclosporine in a model of AVR have prolonged survival compared to controls. hTBM reduced the inflammatory reaction in the vein wall in the stasis-induced thrombosis and mouse-to-rat xenograft models and reduced HMGB1 levels in LPS-treated mice. These results indicate that transgenic expression of hTBM has anticoagulant and antiinflammatory effects that are graft-protective in murine models.

Abdominal obesity and carotid artery wall thickness. The Los Angeles Atherosclerosis Study.

OBJECTIVE: To determine whether or not abdominal obesity is associated with the intima-media thickness (IMT) of the carotid artery wall independently of total body obesity and major risk factors for atherosclerosis. DESIGN: : Longitudinal epidemiological study. SUBJECTS: A total of 573 middle-aged employees of a utility company. MEASUREMENTS: Sagittal and transverse abdominal diameters, their ratio and difference were used as measures of abdominal obesity. RESULTS: Abdominal diameters and body mass index (BMI) were significantly associated with blood pressure, serum lipoproteins and fasting insulin. In cross-sectional multiple regression models, the sagittal/transverse ratio and BMI were significantly associated with IMT in the presence of atherosclerosis risk, but the sagittal diameter was not. In longitudinal models, baseline BMI was an independent predictor of IMT progression but the sagittal and transverse diameters were not. CONCLUSION: These findings do not support the hypothesis that abdominal obesity is an independent predictor of carotid artery IMT. The consistent pattern of association of measures of general obesity with carotid artery IMT emphasizes the continuing need for prevention and control of this important risk factor.

Women's health issues in haemodialysis patients.

OBJECTIVES: To describe reproductive health issues in women with end-stage renal disease (ESRD) treated with haemodialysis. STUDY DESIGN: Cross-sectional survey based on structured interviews. SETTING: Nephrology units of two major metropolitan tertiary referral hospitals in Victoria and their satellite dialysis centres between 1 November 1998 to 30 June 1999. METHODS: Women aged 20 years or over in haemodialysis programs. OUTCOME MEASURES: Menstrual status; prevalence of menstrual and climacteric symptoms; use of gynaecological screening; and prevalence of comorbidities that may benefit from hormone replacment therapy. RESULTS: 48 women completed the survey. They were similar to the 485 women undergoing haemodialysis in Victoria in age (mean age, 55.5 years; range, 20-84 years), years on dialysis (mean age, 3.9 years; range, 1 month-17 years) and primary diagnosis. Eleven of the 15 premenopausal women reported menstrual cycles of 22-35 days, 13 reported common premenstrual symptoms, and six reported dysmenorrhoea that interfered with daily activities. Average age at menopause was 47.7 years (95% CI, 45.6-49.9 years), and six of the 31 postmenopausal women underwent menopause before 45 years. Eight had ever been prescribed hormone replacement therapy (oral in all cases). Over half the women (26) had not had a Pap smear in the last two years, and 12 of those aged over 50 (38%) had not had a mammogram in the same period. CONCLUSION: Despite their risk of early menopause, cardiovascular disease and bone fracture, few women undergoing haemodialysis were offered hormone replacement therapy. Nor were they adequately screened for gynaecological cancers. Women's health issues seem to be neglected among haemodialysis patients.

Oxygenated carotenoid lutein and progression of early atherosclerosis: the Los Angeles atherosclerosis study.

BACKGROUND: Carotenoids are hypothesized to explain some of the protective effects of fruit and vegetable intake on risk of cardiovascular disease. The present study assessed the protective effects of the oxygenated carotenoid lutein against early atherosclerosis. EPIDEMIOLOGY: Progression of intima-media thickness (IMT) of the common carotid arteries over 18 months was determined ultrasonographically and was related to plasma lutein among a randomly sampled cohort of utility employees age 40 to 60 years (n=480). Coculture: The impact of lutein on monocyte response to artery wall cell modification of LDL was assessed in vitro by quantification of monocyte migration in a coculture model of human intima. Mouse models: The impact of lutein supplementation on atherosclerotic lesion formation was assessed in vivo by assigning apoE-null mice to chow or chow plus lutein (0.2% by weight) and LDL receptor-null mice to Western diet or Western diet plus lutein. IMT progression declined with increasing quintile of plasma lutein (P for trend=0.007, age-adjusted; P=0.0007, multivariate). Covariate-adjusted IMT progression (mean+/-SEM) was 0.021+/-0.005 mm in the lowest quintile of plasma lutein, whereas progression was blocked in the highest quintile (0.004+/-0.005 mm; P=0.01). In the coculture, pretreatment of cells with lutein inhibited LDL-induced migration in a dose-dependent manner (P<0.05). Finally, in the mouse models, lutein supplementation reduced lesion size 44% in apoE-null mice (P=0.009) and 43% in LDL receptor-null mice (P=0.02). CONCLUSIONS: These epidemiological, in vitro, and mouse model findings support the hypothesis that increased dietary intake of lutein is protective against the development of early atherosclerosis.

Work-related stress and early atherosclerosis.

The purpose of this study was to examine the link between work-related stress and early atherosclerosis as measured by common carotid artery intima-media thickness and focal lesions in the common carotid artery and bifurcation. Four hundred sixty-seven members of an occupational cohort (total N = 573) were examined via questionnaires and B-mode ultrasound. We used multiple linear and logistic models to regress lesion risk and intima-media thickness on work-related stress scores from a questionnaire administered at an 18-month follow-up examination. In an age-adjusted model, the prevalence of carotid lesions among men scoring in the highest stress quintile was 36% compared with 21% among men in the lowest quintile. We also observed an increase in intima-media thickness in the highest quintile relative to the lowest (difference = 0.048 +/- 0.025 mm) among men. Among women, stress was not related to the prevalence of lesions or intima-media thickness. These findings suggest that men with greater work-related stress are at increased risk for atherosclerotic disease. Women in this age group may be protected from such effects, or current work-place questionnaires may not accurately assess stress in women.

Children's beliefs about long-term health effects of alcohol and cocaine use.

OBJECTIVE: To assess age differences in children's beliefs about the long-term health effects of alcohol and cocaine, to use such beliefs to predict attitudes toward and intentions to use these substances, and to establish whether accurate beliefs are more predictive than inaccurate ones. METHODS: Children ages 6 to 12 (N: = 217) responded to an open-ended question about the effects of long-term alcohol and cocaine use and to 12 structured questions asking whether each produces alcohol-like, cocaine-like, and tobacco-like effects. RESULTS: Differentiation among alcohol, cocaine, and tobacco effects was limited but increased with age. Beliefs about health effects had no impact on alcohol attitudes and intentions, but intentions to drink were stronger among older and white children. Anti-cocaine attitudes and intentions were associated with being older and non-White and with having accurate knowledge of cocaine's true health effects-but also with believing falsely that cocaine has tobacco-like effects and that drugs in general have catastrophic effects. CONCLUSIONS: With age, and as predicted by Werner's orthogenetic principle, children differentiated more sharply between substances. Although negative misconceptions can contribute to anti-drug attitudes and intentions, children should nonetheless be taught about the distinct effects of different substances on health.

Chronic intestinal pseudo-obstruction in systemic lupus erythematosus due to intestinal smooth muscle myopathy.

We report the case of a woman with systemic lupus erythematosus initially manifesting with fever, rash and arthritis, and two years later with Class IV lupus nephritis. Following treatment with cyclophosphamide she developed symptoms and signs of chronic intestinal pseudo-obstruction (CIPO) that was initially thought to be due to a neutropenic enterocolitis. However, persistence of symptoms resulted in segmental resection of the ileum which showed widespread myocyte necrosis and active inflammation within the muscularis propria. A subsequent, more extensive ileocolic resection showed severe diffuse atrophy and fibrosis of the muscularis propria throughout the resected bowel. The absence of mesenteric vasculitis and the clinical response of the CIPO to the immunosupressive regimen of prednisolone and cyclosporin A suggest that the bowel muscle coat changes reflect an intestinal myopathy secondary to systemic lupus erythematosus, and may have an auto-immune etiology.

Blood pressure, LDL cholesterol, and intima-media thickness: a test of the "response to injury" hypothesis of atherosclerosis.

The "response to injury" hypothesis is a plausible model of the development of atherosclerosis supported by observations from animal models. The present study uses epidemiological data to investigate the hypothesis that wall damage due to hypertension is a precursor of low density lipoprotein cholesterol (LDL-C)-mediated atherosclerosis. The Los Angeles Atherosclerosis Study is following a cohort of 576 participants who were aged 40 to 60 years and were free of symptomatic cardiovascular disease at recruitment. Common carotid artery intima-media thickness (IMT) was assessed by B-mode ultrasonography. After exclusion for nonfasting blood draw and other missing data, 511 subjects were available for analysis. IMT was regressed on LDL-C within tertiles of systolic blood pressure (SBP): low (93 to 122 mm Hg), middle (123 to 132 mm Hg), and high (133 to 175 mm Hg). Covariates were age, sex, body height, body mass index, ethnicity, smoking status, diabetes, and pharmacological treatment for hypertension or hypercholesterolemia. IMT was significantly related to LDL-C in the high SBP group (beta=0.025+/-0.008, where beta values are IMT [mm]/LDL-C [mmol/L]; P=0.002) but not in the middle (beta=-0.006+/-0.008, P=0.39) or low (beta=-0.004+/-0.009, P=0.64) SBP group. The slope in the high SBP group was significantly greater than in the middle (P=0.004) or low (P=0.014) SBP group. Results were similar for women and men, and after the exclusion of diabetics and persons using antihypertensive or lipid-lowering medications. Elevated LDL-C was associated with increased IMT in the upper tertile of SBP but not in the lower tertiles. These findings are consistent with the hypothesis that wall injury due to elevated SBP increases the susceptibility of the artery wall to LDL-C-mediated atherogenesis.

Automated intima-media thickness: the Los Angeles Atherosclerosis Study.

Common carotid artery (CCA) intima-media thickness (IMT) from B-mode ultrasound is a widely used measure of early atherosclerosis. This study evaluated within- and between-sonographer reproducibility of automated edge-tracking IMT using a low-cost mobile scanner. B-mode images of the left and right CCA were acquired on two occasions (interval of 2-14 days) by two sonographers for 38 subjects, aged 31-75 y. Reproduciblity error was measured as the mean absolute difference (MAD+/-SEM) and the standard deviation of differences (SDdelta) between repeated measurements. Within-sonographer (MAD=0.027+/-0.006 mm; SDdelta=0.044 mm) and between-sonographer errors (MAD=0.041+/-0.008 mm; SDdelta=0.064) in IMT (mean=0.74, SD=0.14) of a single artery were small compared to those of other protocols. Combined averaging across both body positions and arteries reduced intersonographer MAD by 47% (MAD=0.022+/-0.003 mm; SDdelta=0.029 mm). These data demonstrate that the proposed IMT protocol reduces reproducibility error by more than 50% relative to several protocols used in other major studies.

Dietary calcium, calcium supplementation, and blood pressure in African American adolescents.

BACKGROUND: Intake of calcium from the diet is inversely associated with blood pressure in observational studies and animal models but randomized trials in humans have found only small effects of calcium supplementation on blood pressure. A blood pressure-lowering effect of calcium supplementation may thus be restricted to persons with a low intake of calcium from the diet and specific genetic or other characteristics. OBJECTIVE: A randomized trial was conducted to assess the effect of calcium supplementation on blood pressure in African American adolescents. Rapid growth during adolescence may increase calcium requirements, and avoidance of milk and milk products by some African Americans can result in low intake of calcium. DESIGN: One hundred sixteen adolescents (65 girls, 51 boys; mean age: 15.8 y) were given calcium (1.5 g/d) or placebo for 8 wk in a randomized, double-blind, crossover design. Blood pressure was measured after 2, 4, and 8 wk. Dietary calcium was determined with a validated food-frequency questionnaire. RESULTS: The net effect (+/-SE) of calcium supplementation on diastolic blood pressure was a reduction of 1.9 +/- 1.1 mm Hg (P = 0.04, one-tailed t test). Blood pressure reduction was greater in adolescents with lower intake of calcium from the diet (P = 0.003, one-tailed t test for interaction): -4.9 +/- 1.6, -2.3 +/- 1.6, and 1.4 +/- 1.8 mm Hg for change in the lower (0.024-0.067 g Ca/MJ), middle (0.069-0.091 g Ca/MJ), and upper (0.093-0.217 g Ca/MJ) tertiles, respectively. No main effect on systolic blood pressure was detected. CONCLUSION: These findings suggest that calcium supplementation may lower diastolic blood pressure in African American adolescents with low dietary intakes of calcium.

Parental drug use and the socialization of AIDS knowledge and attitudes in children.

Children aged 6 to 18 who had a parent enrolled in drug treatment were matched on the child's age, sex, and ethnicity and on the parent's level of education with children from a community sample. They were compared with respect to parents' knowledge of HIV transmission, parents' efforts to teach their children (ages 6 to 18) about HIV and AIDS, and children's knowledge and attitudes regarding AIDS. Children of drug-abusing parents had more direct and indirect experience with people affected by AIDS than other children, and they demonstrated more knowledge of HIV transmission, once other variables were controlled. Overall, however, few group differences in parents' knowledge and socialization efforts or in children's AIDS-related knowledge and attitudes were observed. Although children of drug abusers appear to be learning as much as other children about HIV and AIDS, they nonetheless deserve special attention as a group at risk for HIV infection.

Usefulness of thrombelastography in assessment of trauma patient coagulation.

OBJECTIVE: Thrombelastography (TEG) is used to rapidly assess coagulation abnormalities in cardiac and transplant surgery. The purpose of this study was to investigate TEG in the initial assessment of trauma patient coagulation. METHODS: TEG was performed on 69 adult blunt trauma patients during their initial evaluation. Demographics, history of inherited coagulopathies, medications, TEG parameters, platelet count, prothrombin time/partial thromboplastin time, Revised Trauma Score (RTS), Injury Severity Score (ISS), use of blood products, and outcome were recorded. RESULTS: Mortality was 4.3%. Fifty-two patients demonstrated coagulation abnormalities by TEG; of these, 45 were hypercoagulable (mean ISS 13.1), and seven were hypocoagulable (mean ISS 28.6). Six of the seven hypocoagulable patients received blood transfusions within the first 24 hours. Mean ISS of the 17 patients with normal TEG parameters was 3.7. Logistic regression of ISS, Revised Trauma Score, prothrombin time/partial thromboplastin time, and TEG on use/nonuse of blood products within the first 24 hours demonstrates that only ISS (p < 0.001) and TEG (p < 0.05) are predictive of early transfusion. CONCLUSIONS: The majority of blunt trauma patients in this series were hypercoagulable. TEG is a rapid, simple test that can broadly determine coagulation abnormalities. TEG is an early predictor of transfusion in blunt injury patients.

Dietary calcium, alcohol, and incidence of treated hypertension in the NHANES I epidemiologic follow-up study.

Evidence concerning the relation between dietary calcium intake and development of hypertension is inconsistent. Some of this inconsistency may be due to interaction of this relation with other factors. The current study was designed to test for an interaction between alcohol consumption and the relation of dietary calcium intake to 10-year incidence of hypertension in a sample of the US adult population: the Epidemiologic Follow-up Study (1982-1984) of the First National Health and Nutrition Examination Survey (NHANES I) (1971-1975). Interactive logistic regression models were estimated with incident hypertension defined as self-reported treatment with antihypertensive medication. After exclusion of participants with evidence of hypertension at baseline (resulting n = 6,634), odds ratios for hypertension were estimated for each 1-g/day increase in calcium intake. The relation between dietary calcium and incident hypertension showed significant interactions with frequency of alcohol use (odds ratio (OR) = 1.33 for daily drinkers, OR = 0.84 for others; p = 0.005 for difference), age (OR = 0.75 for < or = 40 years at baseline, OR = 1.00 for > 40 years; p = 0.004), and body mass index, defined as weight (kg) divided by height (m) squared (OR = 0.82 for < or = 26, OR = 1.01 for > 26; p = 0.018). Interactions with sex and race (black vs. white) were not significant (p > or = 0.4). These findings suggest that a protective effect of foods containing calcium on the risk of developing hypertension may vary across levels of alcohol consumption and other risk factors for hypertension.