Biomedical subjects

B Falkner

Publications and source records attributed to B Falkner.

At least 19 recordsLinked to original sources

PubMed2001

Familial factors in the antihypertensive response to lisinopril.

BACKGROUND: Although it is widely recognized that there are familial elements in the pathogenesis of hypertension, remarkably little is known about the influence of family history on response to specific antihypertensive agents. METHODS: This study was designed to address that issue by comparing the depressor response to lisinopril in a dose range of 10 to 40 mg in 74 patients enrolled as sibling pairs. Because all patients were treated with lisinopril, ambulatory blood pressure monitoring (ABPM), an objective measure not influenced by the investigators, was used to assess the primary blood pressure (BP) outcome variable. RESULTS: Diastolic BP was highly correlated between sibling pairs at baseline (r = 0.476; P < .03) and on treatment (r = 0.524; P = .0021). Ethnicity/race had a striking influence on lisinopril dose and response rate. Among African American patients, 23 of 28 reached the top dose of 40 mg/day, whereas only 14 of 36 Caucasian patients reached that dose level. Among Caucasians, 92% responded, and only 48% of African Americans. Responders were characterized by being younger and heavier, having significantly lower microalbuminuria at baseline, higher baseline renal plasma flow (RPF), and higher urinary kallikrein. CONCLUSION: Among Caucasians, the presence of a hypertensive sibling predicts a striking therapeutic response to angiotensin converting enzyme inhibition.

Adolescent↗

PubMed2000

Dietary nutrients and blood pressure in urban minority adolescents at risk for hypertension.

OBJECTIVE: To determine if blood pressure (BP) level is associated with dietary micronutrients in adolescents at risk for hypertension. DESIGN: Adolescents aged 14 to 16 years, with BP higher than the 90th percentile on 2 separate measurements in a school setting, had diet assessments. A 24-hour intake recall was obtained on 180 students (108 boys and 72 girls). Folic acid intake was used as an index of fruit, vegetable, and whole grain intake; the high folate group had a folate intake greater than the recommended daily allowance and the low folate group had a folate intake less than the recommended daily allowance. Data were analyzed by 2-way analysis of variance. RESULTS: Mean diastolic BP was significantly higher in the low folate vs the high folate group (boys: 72 vs. 67 mm Hg; girls: 76 vs. 73 mm Hg; P =.008). The difference in systolic blood pressure was not significant. There was no difference in body mass index between the diet groups. Sodium intake per 4184 kJ was not different. The low folate group had significantly lower intakes per 4184 kJ of potassium (P =.002), calcium (P = .001), magnesium (P<.001), and total intake of beta carotene, cholecalciferol, vitamin E, and all B vitamins. CONCLUSIONS: Among adolescents at risk for hypertension, BP was lower in those with higher intakes of a combination of nutrients, including potassium, calcium, magnesium, and vitamins. Dietary benefits on BP observed on diets rich in a combination of nutrients derived from fruits, vegetables, and low-fat dairy products could contribute to primary prevention of hypertension when instituted at an early age.

Adolescent↗

PubMed2000

The association of RBC sodium-lithium countertransport (Vmax) with left ventricular mass in African American women.

In Caucasian hypertensives and diabetics, increased RBC sodium-lithium countertransporter activity (SLC) is a marker for end-organ complications of vascular disease. A subgroup of African Americans with high Vmax for SLC show strong correlations with dyslipidaemia, insulin resistance, microalbuminuria and higher blood pressure. The purpose of our study was to determine if Vmax in premenopausal African American women correlates with left ventricular mass (LVM) before the onset of clinically diagnosed hypertension. Non-diabetic African American women (n = 35, mean age 31 years) were evaluated for cardiovascular disease risk factors, including anthropometric and blood pressure measurements, oral glucose tolerance test (OGTT), and euglycaemic hyperinsulinaemic clamp for insulin sensitivity. Fasting blood specimens were assayed for SLC activity (Vmax) and lipids. Cardiac structure was determined by 2-D echocardiography. LVM was calculated by the cube root formula and adjusted for height (LVM index). Vmax correlated significantly with average systolic blood pressure (r = 0.45, P = 0.007), diastolic blood pressure (r = 0.48, P = 0.004), mean blood pressure (r = 0.48, P = 0.003) and LVM index (r = 0.40, P = 0.02). Vmax was also associated with fasting insulin (r = 0.39, P = 0.01), the sum of insulin (r = 0.52, P = 0.002), and insulin sensitivity adjusted for fat-free mass (r = -0.55, P = 0.001). There was no statistically significant relationship between Vmax and body mass or lipids. Vmax for SLC correlates with cardiac structure in premenopausal African American women. Vmax is also associated with insulin sensitivity and insulin resistance in this non-diabetic sample. SLC activity may be useful in identifying a subgroup of young African American women with left ventricular hypertrophy and insulin resistance before the onset of clinically diagnosed hypertension and diabetes. Journal of Human Hypertension (2000) 14, 213-219.

Adult↗

PubMed2000

The association of left ventricular mass with cardiovascular risk factors in African American women.

BACKGROUND: African American women have disproportionately high rates of myocardial infarction and stroke. Left ventricular hypertrophy is an independent risk factor for cardiovascular disease. Increases in left ventricular mass (LVM) may precede the expression of hypertension. The purpose of this study was to determine whether LVM is related to cardiovascular risk variables in healthy, premenopausal African American women. METHODS: Normotensive or borderline hypertensive nondiabetic African American women (N = 52; mean age, 31 years) underwent anthropometric and blood pressure measurements, oral glucose tolerance test, euglycemic clamp, fasting lipid profile, and two-dimensional echocardiography. LVM was calculated by the cube root formula and adjusted for height [LVM index (LVMI)]. RESULTS: LVMI correlated with body mass index (r = .36, P = 0.009), systolic blood pressure (r = .44, P = 0.001), diastolic blood pressure (r = .43, P = 0.002), and central body fat (r = .42, P = 0.002). LVMI also directly correlated with lipoprotein (a) (r = .34, P = 0.02). Significant independent relationships of other metabolic variables with LVMI were not detected. DISCUSSION: These data show that increased LVMI is associated with body mass index and central obesity, but not with lipids, insulin resistance, or insulin sensitivity. LVMI is also associated with blood pressure before the expression of severe hypertension in healthy, premenopausal African American women.

Adult↗

PubMed1999

Hyperinsulinism and sex hormones in young adult African Americans.

Hyperinsulinemia is a risk factor for cardiovascular disease, and is linked with non-insulin-dependent diabetes mellitus (NIDDM), hyperlipidemia, obesity, and hypertension. Sex hormones also play a role in the metabolic alterations associated with the risk for cardiovascular disease. A reduction in sex hormone-binding globulin (SHBG) may be predictive of future NIDDM particularly in women. The postmenopausal decline in estrogen is also associated with an increase in risk factor expression in women. Since African Americans experience a greater prevalence of NIDDM, obesity, and hypertension, conditions associated with hyperinsulinemia, the purpose of this study was to determine if alterations in sex hormone levels are associated with the plasma insulin concentration in young adult African Americans, and to determine if there are sex differences in the effect of insulin on lipids and sex hormones. In a sample of 221 nondiabetic African American men (n = 105) and women (n = 116) with a mean age of 31 years, we examined the relationship of the plasma insulin concentration with the body mass index (BMI), blood pressure, plasma lipids, and sex hormones, including free testosterone, estradiol, and SHBG. Plasma insulin increased with the BMI and other measures of adiposity (P<.001) in men and women. Significant correlations of insulin with plasma lipids were also present in both sexes. There was a significant inverse correlation of insulin with SHBG in both men (r = .28, P = .007) and women (r = .27, P = .02). There was a significant direct correlation of insulin with free testosterone in women (r = .032, P<.001). Stepwise multiple regression analyses with insulin as the dependent variable detected the BMI, triglyceride, and apolipoprotein A1 as significant contributors to the plasma insulin concentration in men. In women, the multiple regression model detected percent body fat, low-density lipoprotein (LDL) cholesterol, and free testosterone as significant contributors to plasma insulin. These data on young African Americans demonstrate a significant relationship between hyperinsulinemia and obesity, atherogenic lipid status, and lower SHBG. In the premenopausal women, the lower SHBG is linked with higher free testosterone, favoring a condition of relative androgen excess.

Adult↗

PubMed1999

Low dietary magnesium is associated with insulin resistance in a sample of young, nondiabetic Black Americans.

In both humans and experimental animals, dietary induced magnesium deficiency is correlated with insulin resistance. The purpose of this study was to determine whether dietary magnesium intake is associated with insulin sensitivity or blood pressure in a sample of nondiabetic, young adult black Americans. We also examined dietary calcium, potassium, and sodium intake. The study was conducted on a sample (n = 179) of young adults aged 30 +/- 3.4 years who had been followed longitudinally. Nutrient intake was assessed by obtaining a 24-h recall interview of dietary intake. Intake data were entered in a nutrient analysis program (Nutritionist III), which quantitated micronutrients, macronutrients, and minerals. We classified the sample into insulin-sensitive (IS) and insulin-resistant (IR) groups, according to insulin-stimulated glucose use (M) measured during insulin clamp. M correlated positively with magnesium intake in mg/kg of fat-free mass (r = 0.15, P < .05 overall; in men, r = 0.25, P < .02). There was a significant negative correlation of total dietary magnesium intake with the sum of insulin levels measured during an oral glucose tolerance test (OGTT) (r = -0.13, P < .05). When corrected for body fat, in men there was also a significant correlation of dietary magnesium intake, measured in mg/kg of fat-free mass, with the sum of insulin concentrations on the OGTT (r = -0.22, P < .05). When cases were categorically classified as IS versus IR, magnesium intake in mg/kg of fat-free mass was lower in IR (2.97 +/- 1.4) than in IS (3.68 +/- 2.2; P = .022). These results suggest a possible role for dietary magnesium in insulin resistance.

Adult↗

PubMed1999

A study of the metabolism of apolipoprotein B100 in relation to insulin resistance in African American males.

The purpose of this study was to determine the relationship between insulin resistance and apoB100 metabolism in African American males. Fifteen subjects, 33 +/- 7.6 years old, were divided into two groups, insulin-resistant (IR) or insulin-sensitive (IS), based on the sum of the plasma insulin concentrations during an oral glucose tolerance test. The IR group (n = 8) differed significantly from the IS group (n = 7) with respect to body mass index (BMI) (30.1 vs 23.1 kg/m2; P = 0.0003), fasting triglycerides, (118 vs 54 mg/dl, P = 0. 013), and total plasma apolipoprotein B100 (80 vs 59 mg/dl, P = 0.014). Significantly elevated apoB100 levels in the IR group were seen in very low density lipoprotein (VLDL) (5.1 vs 3.4 mg/dl, P = 0.045) and intermediate density lipoprotein (IDL) (18 vs 12 mg/dl, P = 0.017) but not in low density lipoprotein (LDL) (57 vs 46 mg/dl, P = 0.19). Total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A-I, and blood pressure were not significantly different between the two groups. There was a high correlation between the sum of insulins during the oral glucose tolerance test and the BMI (rho = 0.88, P = 0.0001). In five IR and five IS subjects, apoB100 kinetics were determined in the fasting state using a bolus dose of deuteroleucine and multicompartmental modeling. IR subjects had significantly lower fractional catabolic rates (FCR) in the larger VLDL1 (-70%), the smaller VLDL2 (-71%), and the IDL (-53%) fractions. No significant differences in production rates were observed for any lipoprotein class. There was a significant correlation between the sum of insulins and the FCR of the apoB100 of VLDL1 (rho = -0.65, P = 0.05) and of IDL (rho = -0.85, P = 0.004). The correlation coefficient of the sum of insulins and the FCR of VLDL2 was -0.61 with P = 0.067. We conclude that in this population of African American males, IR is correlated with a decreased FCR of apoB100 in VLDL and IDL and elevated plasma levels of apoB and triglycerides (TG). These changes might be explained by decreased clearance of the TG-rich lipoproteins. We postulate that this may reflect decreased lipoprotein and/or hepatic lipase activity related to insulin resistance and its association with obesity.

Adult↗

PubMed1999

Dietary compliance among salt-sensitive and salt-insensitive normotensive adults.

Little is known about the customary level of sodium intake by salt-sensitive people and the nature of obstacles they face in the adoption of a reduced-sodium diet. These issues were addressed with 12 salt-sensitive (SS) and 9 salt-insensitive (SI) normotensive adults. Information about sodium consumption, taste, and blood pressure and concerns about following a diet reduced in sodium were collected at baseline and monthly while participants followed a 100 mmol Na/day diet for 4 months. Mean sodium intakes of both groups were comparable at baseline and were reduced significantly during diet. The principal dietary concerns were reduced food availability, increased food costs, and reduced food palatability. There were no group differences. Ratings declined over time, but only the food palatability issue did so significantly because of a shift by the SI only. While the predictive value of SS classification remains uncertain, these data indicate that dietary change is feasible in SS subjects.

Adult↗

PubMed1999

Blood pressure increase with impaired glucose tolerance in young adult american blacks.

Hypertension and non-insulin-dependent diabetes mellitus are more prevalent in blacks than whites. The convergence of these 2 disorders augments the expression and severity of cardiovascular disease. The purpose of this study was to determine whether alterations in glucose metabolism are related to an increase in blood pressure (BP). This study was conducted on 304 nondiabetic blacks (mean age=32 years). Measurements in all subjects included BP, anthropometric measures, oral glucose tolerance test, insulin clamp to measure insulin sensitivity, and plasma lipids. The sample was stratified according to plasma glucose on oral glucose tolerance test to normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetes mellitus (DM). A 2-way ANOVA was performed to determine differences between the metabolic groups. With the use of American Diabetic Association criteria, 20.4% of the samples were classified as IGT and 5.9% were diabetic. A significant increase in BP existed from NGT to IGT to DM, which was stronger in women than men (systolic blood pressure in women: NGT=122, IGT=127, and DM=140 mm Hg, P<0.001) with a significant linear trend (P<0.001). With the use of body mass index as a covariate, the group difference in BP remained significant (P=0.006). Measures of insulin sensitivity demonstrated significant metabolic group differences (P<0.001) with a linear trend (P<0.001) of decreasing insulin sensitivity from NGT to DM. These results indicate that early alterations in glucose metabolism effects an upward shift in BP. The higher BP in IGT and DM may be due to vascular endothelial cell resistance to insulin action.

Adult↗

PubMed1999

Sex differences in African-Americans regarding sensitivity to insulin's glucoregulatory and antilipolytic actions.

OBJECTIVE: The purpose of this study was to determine if there are sex differences in African-Americans regarding the effect of obesity on sensitivity to insulin as a glucoregulatory and antilipolytic hormone. RESEARCH DESIGN AND METHODS: Data from study participants, 127 nondiabetic African-Americans (mean age 32 +/- 4 years), included anthropometric measurements, an oral glucose tolerance test (OGTT), a 2-h euglycemic-hyperinsulinemic clamp, and a fasting triglyceride level. Sensitivity to insulin as a glucoregulatory hormone was determined by M/FFM, where M is the mean glucose infusion rate during the second hour of the clamp and FFM is fat-free mass. Sensitivity to insulin's antilipolytic action was assessed during the OGTT by the percent suppression of free fatty acid (FFA) concentrations between 0 and 120 min. The higher the suppression of FFAs, the greater the sensitivity to insulin's antilipolytic action. RESULTS: The participants were classified by BMI into three groups: nonobese (31 men, 24 women), obese (17 men, 14 women), and severely obese (12 men, 29 women). The women had higher percentages of body fat (P < 0.001), and the men had greater FFM (P < 0.001). The M/FFM values for men versus women in each BMI group were nonobese, 8.8 +/- 2.8 vs. 10.8 +/- 4.4; obese, 7.2 +/- 3.4 vs. 8.5 +/- 3.4; and severely obese, 4.7 +/- 2.1 vs. 6.1 +/- 2.2. The difference between the BMI groups was significant (P < 0.001), as was the difference between men and women (P < 0.01). In addition, there was a significant sex difference in percent suppression of FFAS (P < 0.001). The men and women had similar fasting insulin and FFA concentrations; however, in the men only, the percent suppression of FFA declined with increasing obesity (nonobese, 83 +/- 15%; obese, 73 +/- 18%; and severely obese, 69 +/- 19%; P = 0.02). The women in all three BMI groups had lower FFA levels of 86-88%. CONCLUSIONS: Obese African-American men and women are resistant to insulin as a glucoregulatory hormone, but only obese men are resistant to insulin's antilipolytic action; obese African-American women are sensitive to insulin's antilipolytic action. The combined presence of sensitivity to insulin's antilipolytic action with resistance to insulin's glucoregulatory action in obese African-American women may contribute to their high prevalence of obesity and type 2 diabetes.

Adult↗

PubMed1999

Salt-sensitivity classification in normotensive adults.

The objectives of this study were to assess the reliability, sensitivity and specificity of salt-sensitivity classification in normotensive adults and to determine the predictive power of four clinical indices for salt-sensitivity. A total of 66 healthy, normotensive, free-living adults were administered 11-day salt-sensitivity diagnostic dietary salt challenges on two occasions to permit assessment of classification test-retest reliability. An oral glucose tolerance test, an acute saline loading test, gustatory testing and determination of salivary flow and sodium concentration were carried out to assess (by correlation analysis) their predictive power for salt-sensitivity. Following these procedures, 21 participants followed a reduced-sodium diet for 4 months, during which blood pressure was monitored monthly to allow evaluation of salt-sensitivity classification sensitivity and specificity. Regression was used to develop a predictive model for salt-sensitivity. Salt-sensitivity classification was not highly reliable (kappa-value=0.38), sensitive (0.73) or specific (0.60). No single index was highly predictive of classification status, but a model composed of five indices accounted for 92% of the variance in blood pressure response to acute salt challenge. The dietary salt challenge procedure used here for salt-sensitivity classification of normotensive adults had low test-retest reliability. While a battery of easily measured attributes may facilitate rapid salt-sensitivity classification, such a diagnosis provides only limited insight regarding blood pressure responsiveness to chronic dietary salt restriction in normotensive adults.

Adult↗

PubMed1998

Relationship of leptin concentration to gender, menopause, age, diabetes, and fat mass in African Americans.

This investigation was designed to determine the relationship of leptin concentration to gender, sex hormones, menopause, age, diabetes, and fat mass in African Americans. Participants included 101 African Americans, 38 men (mean age, 34.2 +/- 7.4 years), 29 age-matched premenopausal women (mean age, 32.6 +/- 3.7 years), and 36 postmenopausal women (mean age, 57.8 +/- 5.9 years). The women were not taking exogenous sex hormones, and 12 subjects were diabetic. Percent body fat was calculated with the Siri formula, fat mass (FM) was calculated as weight x percent body fat, and Fat-free mass (FFM) was calculated as weight minus FM. Fasting plasma was assayed for leptin, estradiol, free testosterone, glucose, and insulin concentrations. The nondiabetics had an oral glucose tolerance test (OGTT). The diabetics compared with the non-diabetics had a higher central fat index (p=0.04) but otherwise were similar to nondiabetics in all parameters measured. Body mass index, percent body fat, and FM were greater in women than men (p<0.001). Leptin concentrations in men, premenopausal, and postmenopausal women were: 7.51 +/- 8.5, 33.9 +/- 17.3, 31.4 +/- 22.3 ng/mL. Leptin/FM x 100 in the three groups were: 28.9 +/- 16.1, 98.65 +/- 44.9, 77.1 +/- 44.5 ng/mL/kg. The gender difference in leptin concentration and leptin/FM was significant (p<0.001), but the difference between premenopausal and postmenopausal women was not. In each group, weight, percent body fat, and FM were highly correlated with leptin concentration. Multiple regression analyses with leptin concentration as the dependent variable and age, diabetic status, percent body fat, weight, FM, FFM, estradiol, and free testosterone concentrations as independent variables demonstrated that the determinants of leptin concentration in men was weight only (R=0.83, p<0.001), in premenopausal women it was FM only (R=0.57, p<0.001), and in postmenopausal women it was weight only (R=0.67, p<0.001). With diabetics excluded, the multiple regression analysis was repeated with fasting insulin concentration and the area under the insulin curve during the OGTT included as independent variables. The results for this multiple regression analyses were the same as the first. Therefore, leptin concentration in African Americans is determined by gender and fat mass. Menopause, age, and diabetes do not affect leptin concentration.

Adult↗

PubMed1998

Can cardiovascular risk be predicted by newborn, childhood, and adolescent body size? An examination of longitudinal data in urban African Americans.

OBJECTIVE: Recent retrospective studies of older adults have demonstrated a correlation between lower birth weight and hypertension and insulin resistance. We tested this finding in our sample of urban African Americans with prospective data on growth and blood pressure and also tested other variables (in addition to birth weight) for their relationship to adult cardiovascular risk. STUDY DESIGN: A prospective study of birth weight, growth, and blood pressure (Philadelphia Perinatal Collaborative Project) followed a sample of 137 African Americans, with nine examinations from birth through 28.0 +/- 2.7 years. Metabolic measurements (oral glucose tolerance testing, euglycemic hyperinsulinemic clamp, and plasma lipid concentration) were performed on the subjects as adults. Bivariate correlations among parameters were computed using the Pearson r. The chi-squared statistic was used to determine associations of outcomes with birth weight. Stepwise multiple linear regressions were computed using newborn, early childhood, adolescent, and young adult parameters to predict adult outcomes. RESULTS: Birth weight and blood pressure at age 28 years are not correlated (Pearson r = 0.06). Birth weight is also unrelated to adult obesity. However, weight at 0.3 years and after and body mass index at 7 years and after are correlated with adult weight. Furthermore, weight at age 14 years is significantly negatively correlated with measures of insulin-stimulated glucose use, indicating that obese adolescents may be at greater risk than nonobese adolescents for development of non-insulin dependent diabetes in adulthood. CONCLUSIONS: We found no relationship between birth weight and adult outcomes pertaining to cardiovascular risk in this sample of adult African Americans. However, we did find evidence that somatic growth (body weight and body mass index) is significantly related to obesity and attenuated insulin-stimulated glucose utilization in adulthood. These findings indicate that the origins of adult cardiovascular disease are related to somatic growth, but not intrauterine growth, and are evident during childhood.

Adolescent↗

PubMed1998

Nocturnal reduction of blood pressure and the antihypertensive response to a diuretic or angiotensin converting enzyme inhibitor in obese hypertensive patients. TROPHY Study Group.

During a 12-week, multicenter study to evaluate the efficacy and safety of lisinopril and hydrochlorothiazide (HCTZ) for the treatment of obesity-related hypertension, ambulatory blood pressure (ABP) monitoring was performed both at baseline and at study completion in 124 patients. Patients were randomized to three groups: placebo, lisinopril (10, 20, or 40 mg/day), or HCTZ (12.5, 25, or 50 mg/day). All groups were matched with regard to sex, race, age, body mass index, and waist/hip ratio. The primary analysis of ABP data revealed that both lisinopril and HCTZ effectively lowered mean 24-h systolic (SBP) and diastolic (DBP) blood pressure compared with placebo, (mean change from baseline SBP/DBP: -12.0/-8.2, -10.6/-5.5, and -0.3/-0.5 mm Hg, respectively); however, lisinopril lowered DBP better than HCTZ (P < .05). Secondary analyses of groups revealed that men responded better to lisinopril than HCTZ (-11.9/-7.3 v -6.6/-3.5 mm Hg, respectively), whereas women responded well to both drugs. White patients responded better to lisinopril than HCTZ, whereas black patients showed a significant response to HCTZ only. Response to treatment was also influenced by patient classification of 24-h blood pressure profiles, ie, "dipper" or "nondipper." Overall, the majority of obese hypertensives were nondippers. Nondippers (n = 82) responded well to both drugs (-10.4/-6.9 v -12.5/-5.7 mm Hg, P < .05 v placebo), whereas dippers (n = 42) responded to lisinopril (-11.7/ -9.4 mm Hg, P < .05 v placebo and HCTZ), but not HCTZ (-5.6/-4.1 mm Hg, P = NS v placebo). Results of 24-h ABP data show that both lisinopril and HCTZ are effective therapies for obesity-related hypertension and that response to treatment is influenced by sex, race, and dipper/nondipper status.

Adult↗

PubMed1998

Birth weight versus childhood growth as determinants of adult blood pressure.

In older white American adults, recent retrospective studies have demonstrated a relationship between lower birth weight and hypertension. Black Americans have a higher occurrence of both lower birth weight and hypertension than do white Americans. To test the low birth weight-high blood pressure hypothesis, data from a prospective study (Perinatal Collaborative Project) were examined. The study followed a sample of 137 black Americans, with nine examinations. Data on birth weight, growth, and blood pressure from birth through 28.0+/-2.7 years were obtained longitudinally. Bivariate correlations among parameters were computed with the Pearson r. Birth weight and blood pressure at age 28 years are not correlated (Pearson r=.06). However, systolic blood pressures measured at 0.3 years and thereafter are correlated with adult systolic blood pressure. Also, weight at 0.3 years and body mass index at 7 years and thereafter are correlated with adult weight. Our data did not confirm the birth weight-blood pressure hypothesis. Rather, we detected significant correlations between preadult measurements of blood pressure and weight with adult measurements. These results indicate that in black Americans, childhood growth is a stronger determinant than intrauterine growth of adult blood pressure.

Adult↗

PubMed1997

The relationship in African-Americans of sex differences in insulin-mediated suppression of nonesterified fatty acids to sex differences in fasting triglyceride levels.

Insulin is a potent antilipolytic hormone that promotes the deposition of fat and decreases the release of nonesterified fatty acids (NEFA) from adipose tissue. The purpose of this study was to investigate in African-Americans (AAs) sex differences in insulin-mediated suppression of plasma NEFA and fasting triglyceride (TG) levels. Ninety AAs, 44 men and 46 women with a mean age of 34 +/- 8 years were classified by body mass index (BMI) into three groups: non-obese (22 men and 18 women), obese (12 men and 10 women), and severely obese (10 men and 18 women). In each BMI group, women versus men had greater percent body fat (non-obese, 30 +/- 6 v 18 +/- 6, P < .001; obese, 36 +/- 3 v 26 +/- 2, P < .001; and severely obese, 39 +/- 4 v 29 +/- 4, P < .001). An oral glucose tolerance test (OGTT) was performed with fasting TG levels and plasma insulin and NEFA concentrations obtained at 0, 30, 60, and 120 minutes. In women, insulin-mediated NEFA suppression was similar in each of the three BMI groups (non-obese, 85% +/- 14%; obese, 88% +/- 11%; and severely obese, 87% +/- 10%; P = .8). In men, the percent suppression of NEFA declined with increasing obesity (non-obese, 83% +/- 14%; obese, 71% +/- 21%; and severely obese, 68% +/- 16%; P = .04). Changes in NEFA suppression were reflected in the fasting TG levels. TG levels in women were similar in each BMI group (non-obese, 71 +/- 39 mg/dL; obese; 69 +/- 21; severely obese, 79 +/- 30; P = .7). In contrast, fasting TG levels for men were higher in the higher BMI groups. Plasma TG levels in men were 87 +/- 41 mg/dL for obese, 113 +/- 65 for obese, and 169 +/- 81 for severely obese (P = .001). These data demonstrate sex differences in insulin-mediated NEFA metabolism. In AA women, the maintenance of sensitivity to insulin-mediated suppression of NEFA regardless of the degree of obesity may contribute to the normal plasma TG levels. For AA men, the resistance to insulin-mediated suppression of NEFA in the higher BMI categories may allow more NEFA to be released from adipose tissue into the circulation and available to the liver for synthesis into TG-containing lipoproteins.

Adult↗

PubMed1997

Sodium-lithium countertransport is associated with insulin resistance and urinary albumin excretion in young African-Americans.

Increased activity of the sodium transporter, sodium-lithium countertransport (SLC), is reported in hypertensive white patients with evidence of cardiac and renal injury. The purpose of this study was to determine whether increased SLC activity detects risk for nephropathy or vascular disease in nondiabetic, young adult African-Americans. We examined 85 African-Americans aged 25 to 33 years with measurement of blood pressure, an oral glucose tolerance test to measure insulin response to glucose challenge, and an insulin clamp for insulin sensitivity (M). Fasting plasma lipids were measured, and the Vmax and Km for Na+ were assayed on red blood cells. Urinary albumin excretion (UAE) was measured on timed collections. There was a statistically significant correlation of the Vmax for SLC with M (r = -0.26, P = 0.02) and with UAE (r = 0.25, P = 0.02). The Km for Na+ to activate SLC was also elevated in the subgroup of subjects with elevated Vmax of SLC. There was no significant correlation of SLC with blood pressure in bivariate analysis. Step-wise multiple linear regression analysis of all variables on the Vmax SLC demonstrated that plasma triglyceride, UAE, body mass index, systolic blood pressure, M, and fasting insulin were step-wise selected into the linear regression model (F-ratio = 3.2, df = 77, R = 0.46, P < 0.009). In this young adult African-American population, elevated SLC activity is detected in association with metabolic and lipid alterations typical of insulin resistance. Elevated SLC activity is also associated with higher rates of UAE, suggesting possible evidence of early renal injury.

Adult↗

PubMed1997

Blood pressure response to sodium in children and adolescents.

The predisposition to primary hypertension is composed of genetic factors, and aberrant mechanisms leading to the clinical expression of hypertension may be operational in children and adolescents. Dietary composition may play a role in the expression of hypertension. The effects of diet on blood pressure in the young may be indirect, reflecting the relation of diet with growth and body composition. Alternatively, there may be a direct effect of a specific dietary factor, such as sodium, on mechanisms regulating blood pressure. The average daily sodium intake by children and adolescents exceeds recommended amounts. Despite the high sodium intake among children, there are few data showing that decreasing sodium intake lowers blood pressure. Children who do express blood pressure sensitivity to sodium intake also have related risk factors for cardiovascular disease such as a positive family history or obesity. Prospective data are needed in children with characteristic risk factors to determine whether sodium intake contributes to the pathogenesis of hypertension and whether this course can be modified by alterations in diet.

Adolescent↗