Retinoid-X receptors and the effects of 9-cis-retinoic acid on insulin secretion from RINm5F cells

Retinoid-X receptors (RXRs) are 9-cis-retinoic acid (9CRA)-dependent gene transcription factors, which modulate the action of all-trans-retinoic acid (ATRA), fatty acids, thyroid hormone (TH), and vitamin D (VD) by forming dimers with themselves or ATRA, TH, peroxisome proliferator activator receptors (PPARs), or VD receptors (VDRs). To determine if 9CRA and RXRs have a role in secretion, RINm5F cells were assayed for RXR transcripts and effects of 9CRA and ATRA on secretion. A single RXR alpha transcript and two RXR beta transcripts, but not RXR gamma, were evident by Northern blot. Cells were cultured for 48 hours without and with 9CRA 1 to 1,000 nmol/L and then stimulated with glucose 0, 0.5, 2.8, 7, and 11 mmol/L 9CRA increased secretion at each glucose concentration, 9CRA increased secretion by 50% to 100% (ANOVA, P < .001) with consistent concentration-dependent responses (eg. at glucose 2.8 mmol/L 9CRA: 0 nmol/L, 5.02 +/- .20 ng/(10(6) cells.h); 1 nmol/L, 6.97 +/- .30; 10 nmol/L, 8.36 +/- .18; 100 nmol/L, 9.15 +/- .28; 1,000 nmol/L, 10.24 +/- .24; n = 6). Although RINm5F cells respond slightly if at all to glucose, 9CRA facilitated glucose-induced insulin release (eg, at 9CRA 100 nmol/L, glucose: 0.5 mmol/L, 7.47 +/- .22 ng/(10(6) cells.h); 2.8 mmol/L, 9.15 +/- .27; 7 mmol/L, 9.81 +/- .19; 11 mmol/L, 11.16 +/- .23; n = 6). ATRA increased secretion by 28% to 57% (ANOVA, P < .001: at glucose 2.8 mmol/L, ATRA: 0 nmol/L, 6.17 +/- .32 ng/(10(6) cells.h); 1 nmol/L, 7.91 +/- .29; 10 nmol/L, 9.75 +/- .14; 100 nmol/L, 9.66 +/- .33; n = 6). 9CRA was more potent than ATRA (eg, at 2.8 mmol/L; baseline, 8.17 +/- .32 ng/(10(8) cells.h); ATRA 100 nmol/L, 9.66 +/- .33; 9CRA 100 nmol/L, 10.81 +/- .15; P < .05, n = 6). When 9CRA was combined with ATRA, the combination was not additive or synergistic (eg, at 2.8 mmol/L: ATRA 100 nmol/L, 9.66 +/- .33 ng/(10(6) cells.h); 9CRA 100 nmol/L, 10.81 +/- .15; ATRA 100 nmol/L + 9CRA 100 nmol/L, 10.79 +/- .28; P < .05, n = 6). These studies show that (1) 9CRA stimulates insulin secretion from RINm5F cells. This effect appears to be at least equal to if not greater than that observed with ATRA, but additive or synergistic effects with ATRA were not evident; (2) 9CRA may facilitate glucose-induced release; and (3) multiple RXR transcripts are present in insulin-secreting cells, implying specific functions. Our findings support the idea that the effects of 9CRA on insulin secretion are mediated through RXR homodimers or heterodimers with retinoic acid receptors (RARs) or possibly other nuclear receptors. Retinoid deficiency or alterations in retinoid receptor function could lead to abnormalities of cell growth or secretion.

Women's health initiative. Why now? What is it? What's new?

Studies collectively named the Women's Health Initiative (WHI) are currently enrolling 164,500 postmenopausal women in several overlapping clinical trials and an observational study. The overall goals of WHI are to understand the determinants of postmenopausal women's health and to evaluate the efficacy of practical interventions in preventing the major causes of morbidity and mortality in older women. This article reviews the research leading to the WHI studies; describes the study designs and protocols, with an emphasis on what's new about WHI from a psychological perspective; and outlines the major psychosocial hypotheses under investigation and the major challenges WHI presents to psychological science.

Hemodynamic responses to laboratory stressors in children and adolescents: the influences of age, race, and gender

The objectives of the present study were threefold: (a) to compare the patterns of hemodynamic responding of children and adolescents during behavioral challenges, (b) to examine whether previously reported cardiovascular reactivity differences between Black and White children are dependent on pubertal status, and (c) to assess whether gender differences in hemodynamic response reported for adults is similar in children. One hundred fifty-nine children (ages 8-10 years) and adolescents (ages 15-17 years), equally divided along gender and racial lines, participated in a laboratory protocol consisting of a reaction time task, a mirror tracing task, a cold forehead challenge, and a stress interview. Results indicated that adolescents responded with greater beta-adrenergic activation than did children and that gender differences in reactivity often reported for adults emerged more clearly in the adolescents than in the children. This study failed to replicate prior findings of greater vasoconstrictive responses in Black children as compared with White children.

Prevalence and determinants of carotid atherosclerosis in healthy postmenopausal women

BACKGROUND AND PURPOSE

Subclinical atherosclerosis in the carotid arteries can be assessed noninvasively with B-mode ultrasound. Few studies have included enough younger postmenopausal women to examine risk factors specific to this group that were related to subclinical carotid atherosclerosis.

METHODS

A subgroup of 200 participants of the Healthy Women Study underwent B-mode ultrasound of the carotid arteries. Intima-media thickness (IMT) and focal plaque were assessed in each carotid artery. Data regarding risk factors, including blood pressure parameters, lipid values, body mass index, smoking history, and hormone status, were collected at three separate time points (before menopause, 1 year after menopause, and 5 or 8 years after menopause).

RESULTS

The mean IMT was 0.76+/-0.11 mm, and 50% of the population had at least one focal plaque. Smoking had the strongest association with the presence of plaque. Women who smoked at the time of the ultrasound evaluation had five times the odds of having at least one focal plaque compared with women who had never smoked (95% confidence interval, 2.0 to 13.0; P < .01). After we controlled for age and years after menopause, premenopausal values of pulse pressure (P < or = .05), LDL cholesterol (P < or = .05), and a history of smoking (P < or = .01) were independently predictive of plaque. Premenopausal values of triglycerides, pulse pressure, and ever smoking were independently related to average IMT after we controlled for age and years after menopause.

CONCLUSIONS

This study has provided valuable information about the prevalence of carotid atherosclerosis and the risk factors related to carotid atherosclerosis in a group of healthy postmenopausal women.

Women's health initiative. Why now? What is it? What's new?

Studies collectively named the Women's Health Initiative (WHI) are currently enrolling 164,500 postmenopausal women in several overlapping clinical trials and an observational study. The overall goals of WHI are to understand the determinants of postmenopausal women's health and to evaluate the efficacy of practical interventions in preventing the major causes of morbidity and mortality in older women. This article reviews the research leading to the WHI studies; describes the study designs and protocols, with an emphasis on what's new about WHI from a psychological perspective; and outlines the major psychosocial hypotheses under investigation and the major challenges WHI presents to psychological science.

Prospective study of the determinants of age at menopause

The authors prospectively studied the effect of demographic, reproductive, stress-related, and health behavior factors measured at study entry on age of natural menopause in 185 healthy US women. At study entry, women were 42.5-47.5 years old and premenopausal. After a baseline examination (1983-1985), women were followed for 7-9 years, during which time they reported on a monthly basis their menstrual status and whether they were taking hormones. Menopausal age was defined as age at the last menstrual period prior to stopping menstruation for 12 months (and not taking hormones). Estimated median age at menopause was 51.5 years for the whole sample. Median age at menopause was earlier for women who reported irregular menstrual cycles at study entry (50.2 years), were African-American (49.3 years), were smokers (50.6 years), or were currently on a weight reduction diet (50.5 years). Psychosocial stress was predictive of an even earlier median age at menopause in African Americans (48.4 years) and in those with irregular cycles at baseline (49.4 years). Results suggest that premenopausal women in their forties who are experiencing irregular menstrual cycles, are smokers, are dieting, or are African-American are likely to reach menopause earlier than their contemporaries. African-American women may have a different "biological clock" than white women, especially when under stress, or they may experience more stress of longer duration.

A "feminine" model of vulnerability to depressive symptoms: a longitudinal investigation of middle-aged women

The authors hypothesized that having traits associated with the female gender role is related to psychological distress in women. Specifically, they investigated the effect of low instrumentality and high expressivity, private self-consciousness, and anger-in on depressive symptoms measured 3 years later in 460 middle-aged women during the menopausal transition and times of stress. Multivariate analyses showed that after adjustment for depressive symptoms and educational level at study entry, depressive symptomatology 3 years later was higher among women who were low in instrumentality and high in self-consciousness at study entry. Women who were self-conscious were the most vulnerable to a subsequent ongoing stressor, and women who tended to suppress angry feelings and who used hormone replacement therapy when they were postmenopausal had more symptomatology than did other women. The study shows that midlife may be problematic for women with certain female gender role traits.

A longitudinal study of the effects of pessimism, trait anxiety, and life stress on depressive symptoms in middle-aged women

The relative contributions of life stress, menopausal status, and pessimism and trait anxiety during the presence and absence of stress on increases in depressive symptoms across 3 years were examined in a sample of 460 premenopausal women, aged 42-50, who had few depressive symptoms at study entry. Multivariate analyses showed that after statistical adjustments for initial depressive symptoms and education, depressive symptoms at follow-up were higher among women (a) who reported stressful events, especially of a chronic nature, (b) who scored highly on trait anxiety, and (c) who were pessimistic and subsequently experienced a stressful ongoing problem. Change in menopausal status was not related to symptoms. The study confirms that midlife stress and both optimism and trait anxiety are important predictors of depressive symptoms during midlife.

Negative family environment as a predictor of boys' future status on measures of hostile attitudes, interview behavior, and anger expression

The present study tested the hypothesis that family environments characterized as nonsupportive, unaccepting, and conflictual lead to the development of hostile traits in adolescent Caucasian boys. Negative behaviors during parent-son discussions aimed at resolving disagreements were observed in a laboratory setting in 51 intact families. Sons' hostile traits were assessed at the time of the interactions and then 3 years later. Results showed that a high frequency of negative behaviors exhibited by both parents and sons predicted sons' later hostile attitudes and outward expression of anger after adjustment for their initial level of hostile attitudes and anger expression, respectively. A low frequency of positive behaviors exhibited by the father and son predicted sons' later Potential for Hostility ratings after adjustment for their initial level. The meaning of these findings for the conceptualization of hostility is discussed.

Do gender-relevant characteristics determine cardiovascular reactivity? Match versus mismatch of traits and situation

This study tested the hypothesis that individuals exhibit heightened cardiovascular reactivity to a challenging task that is consistent vs. inconsistent with their gender-relevant attributes. In all, 82 men and women categorized as either highly instrumental or expressive engaged in an interpersonal task designed to tap instrumental or expressive characteristics. Results failed to confirm the hypothesis. Expressive individuals tended to exhibit larger increases in systolic blood pressure during an instrumental, relative to an expressive, interaction. Instrumental individuals tended to show larger increases in diastolic blood pressure during an expressive, relative to an instrumental, interaction. These results are consistent with the post hoc interpretation that environmental demands that fall outside of one's perceived areas of competency may result in exaggerated cardiovascular responsivity.

A longitudinal study of the effects of pessimism, trait anxiety, and life stress on depressive symptoms in middle-aged women

The relative contributions of life stress, menopausal status, and pessimism and trait anxiety during the presence and absence of stress on increases in depressive symptoms across 3 years were examined in a sample of 460 premenopausal women, aged 42-50, who had few depressive symptoms at study entry. Multivariate analyses showed that after statistical adjustments for initial depressive symptoms and education, depressive symptoms at follow-up were higher among women (a) who reported stressful events, especially of a chronic nature, (b) who scored highly on trait anxiety, and (c) who were pessimistic and subsequently experienced a stressful ongoing problem. Change in menopausal status was not related to symptoms. The study confirms that midlife stress and both optimism and trait anxiety are important predictors of depressive symptoms during midlife.

Prior to use of estrogen replacement therapy, are users healthier than nonusers?

Observational studies have demonstrated that women who have used postmenopausal estrogen replacement therapy (ERT) are at reduced risk of coronary heart disease. The authors examined whether premenopausal women who subsequently elected to use ERT during menopause had a better cardiovascular risk factor profile prior to use than did nonusers. A total of 541 premenopausal women had their cardiovascular risk factors and psychosocial characteristics evaluated at study entry. After approximately 8 years, 355 women had become postmenopausal, and 157 women reported ERT use during the follow-up period (mean = 93.4 months). The authors compared the premenopausal characteristics of users with those of nonusers. Relative to nonusers, ERT users were better educated (63 vs. 81% with at least some college), and prior to the use of ERT had higher levels of high density lipoprotein (HDL) cholesterol (1.49 vs. 1.59 mmol/liter), HDL2 (0.50 vs. 0.57 mmol/liter), HDL3 (0.98 vs. 1.02 mmol/liter), leisure physical activity (5, 122 vs. 7,158 Kjoules), and alcohol intake (7.5 vs. 9.7 g/day), and lower levels of apolipoprotein B (0.97 vs. 0.90g/liter), systolic blood pressure (112.1 vs. 107.1 mmHg) and diastolic blood pressure (73.8 vs. 71.4 mmHg), weight (68.5 vs. 64.2 kg), and fasting insulin (9.10 vs. 7.66 microU/liter). Prior to use of ERT, in comparison with nonusers, subsequent users reported on standardized questionnaires that they often exhibited Type A behavior, more aware of their feelings, motives, and symptoms, and had more symptoms of stress. Women who elect to use ERT have a better cardiovascular risk factor profile prior to the use of ERT than do women who subsequently do not use this treatment during the menopause, which supports the hypothesis that part of the apparent benefit associated with the use of ERT is due to preexisting characteristics of women who use ERT. This study underscores the widely recognized importance of randomized clinical trials to estimate the direct benefit of postmenopausal ERT for protecting women from cardiovascular disease.

A "feminine" model of vulnerability to depressive symptoms: a longitudinal investigation of middle-aged women

The authors hypothesized that having traits associated with the female gender role is related to psychological distress in women. Specifically, they investigated the effect of low instrumentality and high expressivity, private self-consciousness, and anger-in on depressive symptoms measured 3 years later in 460 middle-aged women during the menopausal transition and times of stress. Multivariate analyses showed that after adjustment for depressive symptoms and educational level at study entry, depressive symptomatology 3 years later was higher among women who were low in instrumentality and high in self-consciousness at study entry. Women who were self-conscious were the most vulnerable to a subsequent ongoing stressor, and women who tended to suppress angry feelings and who used hormone replacement therapy when they were postmenopausal had more symptomatology than did other women. The study shows that midlife may be problematic for women with certain female gender role traits.

Retinoic acid receptor transcripts and effects of retinol and retinoic acid on glucagon secretion from rat islets and glucagon-secreting cell lines

Using intact rat islets, hamster In-R1-G9 cells, and mouse alphaTC-1 clone 9 transgenic tumoral glucagon-secreting cells, we determined the effects of retinol (ROH) and retinoic acid (RA) on glucagon secretion. Since vitamin A effects may be mediated through nuclear RA receptors (RARs) and cytoplasmic ROH- and RA-binding proteins (CRBP and CRABP), cells were also assayed for RARs, CRBP, and CRABP mRNA by Northern blot analyses. Islets and cells were cultured in 2.8 mmol/L glucose and vitamin A-deficient (A-def) medium or in different concentrations of ROH and RA. Using intact islets, RA 10 and 100 nmol/L inhibited glucagon secretion to approximately 60% of control levels. Using In-R1-G9 cells, ROH 0.175 to 5.0 micromol/L inhibited glucagon secretion to 60% to 83% of control levels, and RA 100 and 1,000 nmol/L inhibited glucagon secretion from 72% to 43% of control levels, respectively. Using alphaTC-1 cells, ROH 1.75 micromol/L inhibited glucagon secretion to 80% of control levels, and RA 1 to 100 nmol/L inhibited secretion from 83% to 68% of control levels. Inhibition of secretion was dose-dependent. RARalpha RNA transcripts were detected in alpha TC-1 and In-R1-G9 total RNA extracts; RAR gamma transcripts were detected in alphaTC-1 cells. We conclude the following: (1) ROH and RA inhibit glucagon secretion in cultured rat islets and glucagon-secreting cell lines, and in cell lines the effect of RA is dose-dependent; (2) on a molar basis, RA is on the order of 10- to 100-fold more potent than ROH, a finding consistent with RA being the active metabolite of ROH at the alpha-cell level; and (3) this inhibition may be mediated through classic pathways of retinoid action involving nuclear RARs and gene expression of specific proteins.

Effects of hostility on platelet reactivity to psychological stress in coronary heart disease patients and in healthy controls

Previous studies have demonstrated a potential relationship between psychological stress and platelet activation, which may serve as a link between stress and myocardial infarction (MI). However, the possibility that personality traits associated with coronary heart disease may affect platelet activation has not been adequately investigated. The effect of a laboratory stressor (Type A Structured Interview (SI) and speech task) on platelet activation was assessed in 14 stable post-MI patients and 15 age-matched healthy men, using a standardized method of measuring plasma beta-thromboglobulin (BTG) levels. BTG levels were increased after the stressor (average change = 2.0 ng/ml, p = .005). Increases in BTG with stress were related to higher SI ratings of Potential for Hostility (r = .53, p = .004) and Type A behavior (r = .43, p = .02) but not to Cook-Medley-rated hostility scores. Increases in norepinephrine levels and in diastolic blood pressure were nonsignificantly related to increases in BTG levels (ps < .10), whereas increases in epinephrine levels were unrelated. Despite ceasing aspirin and other platelet inhibitors for 10 days before testing, individuals taking platelet inhibitors before the study had less change in BTG with stress (p = .05). However, after statistical adjustment for this factor, SI ratings of Potential for Hostility were still strongly related to increases in BTG with stress (adjusted r = .56, p = .002). Contrary to expectations, healthy men tended to have greater change in BTG with stress than post-MI patients (p = .06). These results indicate that acute stress increases BTG levels and that hostility is related to greater platelet reactivity, independent of any long term effects of platelet inhibition.

Effects of surgical menopause on psychological characteristics and lipid levels: the Healthy Women Study

The authors examined the effects of surgical menopause, with or without hormone replacement therapy (HRT), on psychosocial functioning and lipid levels in a population-based study of initially premenopausal women. Within 5 years of study entry, 28 women underwent hysterectomy, with 9 retaining their ovaries and 19 having bilateral salpingo oophorectomy (BSO), and with 173 premenopausal women as a comparison group. Women undergoing hysterectomy reported fewer stress symptoms and a more optimistic attitude at follow-up, whereas BSO cases without HRT had lower mean total high-density lipoprotein (HDL) and HDL2, relative to premenopausal women. Subject to limited power, the authors' findings suggest that surgical menopause among middle-aged women does not lead to negative psychological outcomes but that BSO in the absence of hormone use has significant adverse effects on the HDL and HDL2.

Employment and coronary risk in women at midlife: a longitudinal analysis

This study investigated the relation between employment and cholesterol in 541 women aged 42-50 years who resided in Allegheny County, Pennsylvania, in 1985-1988. Employment, health-related variables, and cholesterol were assessed at baseline and 3 years later. At baseline, employed and nonemployed women did not differ in cholesterol or health behaviors. However, women employed at baseline had a significant decrease in total high density lipoprotein cholesterol (1.9 mg/dl) and high density lipoprotein2 cholesterol subfraction (3.2 mg/dl) at follow-up. Those who were employed at both assessments had the lowest high density lipoprotein cholesterol at follow-up. These effects could not be accounted for by sociodemographics or employment quality variables. Post hoc analyses were conducted to examine health behaviors as a potential mechanism to account for the association between employment status and cholesterol. Over the study period, those who were employed at baseline were less likely to increase exercise and more likely to gain weight than those who were not employed at baseline. With menopause-related changes in metabolism, this can result in detrimental effects for cholesterol levels and coronary health. The results highlight the importance of longitudinal assessment in the study of employment and health.

Negative family environment as a predictor of boys' future status on measures of hostile attitudes, interview behavior, and anger expression

The present study tested the hypothesis that family environments characterized as nonsupportive, unaccepting, and conflictual lead to the development of hostile traits in adolescent Caucasian boys. Negative behaviors during parent-son discussions aimed at resolving disagreements were observed in a laboratory setting in 51 intact families. Sons' hostile traits were assessed at the time of the interactions and then 3 years later. Results showed that a high frequency of negative behaviors exhibited by both parents and sons predicted sons' later hostile attitudes and outward expression of anger after adjustment for their initial level of hostile attitudes and anger expression, respectively. A low frequency of positive behaviors exhibited by the father and son predicted sons' later Potential for Hostility ratings after adjustment for their initial level. The meaning of these findings for the conceptualization of hostility is discussed.

Blood pressure reactivity to stress varies by hypertensive status and sex in Nigerians

Previous studies among American and European populations have demonstrated larger blood pressure responses to behavioral challenges among men and hypertensive individuals. This is the first report of cardiovascular responses to behavioral challenges in a West African population. Blood pressure and heart rate changes in mirror image tracing and speech making tasks were recorded for 787 Nigerian civil servants participating in a comprehensive blood pressure survey conducted in Benin City, Nigeria, during 1992. Similar to findings in other populations, greater task-induced increases in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were present among men than women (mean values of SBP = 22.1 vs. 18.3 mmHg, p < 0.001; and DBP means = 13.3 vs. 11.2 mmHg, p < 0.0001) and among hypertensives than normotensives (SBP means = 27.6 vs. 19.2, p < 0.0001; and DBP means = 14.1 vs. 12.1 mmHg, p < 0.05). An elevated prevalence of hypertension among men of higher staff status has been found in this population; however, higher staff status was not consistently related to cardiovascular reactivity, independent of hypertensive status. Additionally, hypertensive men who had speech-induced increases of SBP > 40 mmHg had significantly greater left ventricular mass index than did those hypertensive men with smaller SBP increases (p < 0.04). This study demonstrates that measures of cardiovascular reactivity to behavioral challenges have cross-cultural application, suggesting the need for further investigations of the interrelation of hypertension, cardiovascular reactivity, and left ventricular mass.

Sympathetic reactivity to acute stress and immune response in women

We evaluated if the effects of acute stress on immune parameters were apparent in only the women who showed concomitant and substantial sympathetic nervous system activation and after statistical adjustment for changes in plasma volume. Nineteen women in the follicular stage of their menstrual cycles were assessed for immunological responsiveness to a series of three 3-minute psychological tasks, which reliably elicit cardiovascular and neuroendocrine stress responses. Women were classified as high or low sympathetic reactors based on their cardiovascular and neuroendocrine responses to one of the three tasks, a public speaking task. The stress-induced decreases in CD4+ percentage and increases in natural killer cell number and cytolytic activity were only apparent among the high reactors. Further analysis adjusting for alterations in plasma volume changes showed that the increase in NK cell number remained. Stress-induced proliferative responses to pokeweed mitogen and phytohemagglutinin were not more apparent among high reactors. These results are consistent with the hypothesis that the sympathetic nervous system plays a direct role in modulating the short term response to stress of some indices of the immune system in women.

Are job characteristics related to fibrinogen levels in middle-aged women?

This study examined whether employment status or job characteristics thought to be stressful were related to fibrinogen level in a sample of 161 healthy middle-aged women. Employed women had higher fibrinogen levels than did nonemployed women. Moreover, among employed women, those who perceived high levels of job stress or low support from their bosses had elevated fibrinogen, independent of menopausal status. Perception of low support from one's boss was related to higher fibrinogen levels only among premenopausal women or postmenopausal women who were not using hormone replacement therapy. These results are consistent with the notion that stress associated with some job characteristics influences levels of fibrinogen in women.

Stress-induced hemoconcentration of blood cells and lipids in healthy women during acute psychological stress

This study examined the effects of psychological stress on hemoconcentration in women. Hematologic and hemodynamic variables were assessed in 17 women before and after a 3-min speech task. Significant changes in hematocrit, hemoglobin levels, red and white blood cell (WBC) count, and calculated plasma volume occurred during psychological stress (all ps < .05). Significant increases were also observed for total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol, and free fatty acid (FFA; all ps < .05) during stress. After statistically correcting for the hemoconcentration effects of decreased plasma volume during stress, only WBC count and FFA concentration remained significantly elevated during the stress task (p < .006 and p < .05, respectively). In sum, acute stress alters hemoconcentration in women, which in turn can account for most stress-induced changes in lipids.

Weight threshold and blood pressure in a lean black population

Hypertension is virtually absent in very lean rural African populations but is becoming more common in higher-weight urban African populations and is very common in predominantly obese Westernized black populations. This implies that there is a threshold above which weight is related to blood pressure. We studied urban Nigerian civil servants, a lean population in transition toward a more Westernized lifestyle. Blood pressure, fat-related measurements, fasting insulin, physical activity, alcohol intake, macronutrient intake, and electrolyte excretion were measured in 500 male and 299 female civil servants in Benin City, Nigeria, in 1992. Median body mass index (BMI) was 21.5 kg/m2 in men and 24.0 kg/m2 in women. Examination of age-adjusted mean blood pressure across quantiles of BMI in men and women suggested a threshold of 21.5 kg/m2 below which blood pressure was not correlated with BMI. Above this threshold blood pressure was correlated with BMI. Comparison of groups above and below the lower BMI threshold found that differences in blood pressure-BMI covariation were not explained by differences in alcohol intake, caloric or macronutrient intake, or electrolyte excretion. Physical activity was higher in men below the threshold. Fasting insulin and waist-hip ratio were strongly correlated with BMI even in this very lean population but neither was independently related to blood pressure. We conclude that there is a threshold below which little relationship between blood pressure and weight is observed. Above this threshold even at levels considered lean in US blacks, weight is a major determinant of blood pressure in this population of African blacks, which shares ancestry with US blacks.

Effects of surgical menopause on psychological characteristics and lipid levels: the Healthy Women Study

The authors examined the effects of surgical menopause, with or without hormone replacement therapy (HRT), on psychosocial functioning and lipid levels in a population-based study of initially premenopausal women. Within 5 years of study entry, 28 women underwent hysterectomy, with 9 retaining their ovaries and 19 having bilateral salpingo oophorectomy (BSO), and with 173 premenopausal women as a comparison group. Women undergoing hysterectomy reported fewer stress symptoms and a more optimistic attitude at follow-up, whereas BSO cases without HRT had lower mean total high-density lipoprotein (HDL) and HDL2, relative to premenopausal women. Subject to limited power, the authors' findings suggest that surgical menopause among middle-aged women does not lead to negative psychological outcomes but that BSO in the absence of hormone use has significant adverse effects on the HDL and HDL2.