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1.
A follow-up study on 5442 inhabitants (2699 men, 2743 women) was conducted to determine the association between urinary Ca excretion level and mortality of the general population of three different areas of the Jinzu River basin area, namely, non-Jinzu River, mixed, and the Jinzu River water systems, over a period of 6127 d. More than 98% of the subjects were followed completely in each area. In comparison with the low- and high-Ca-excretion groups (cutoff values; 25.1 mg/dL in men, 20.4 mg/dL in women), the mortality rates per 1000 person-years and standardized mortality ratios (SMRs) tended to be greater in the low-Ca-excretion groups than in the high-Ca-excretion groups in both sexes for each of the three areas. Moreover, Cox’s hazard ratios in men and women of the three areas exhibited negative values, 0.99 except for men of the mixed water system. These values were statistically significant in both sexes for the Jinzu River water system and in women for the non-Jinzu River water system. We conclude that the life-span becomes shorter as urinary Ca excretion levels become lower.  相似文献   

2.
Insulin-like growth factor I (IGF-I) levels in urine were measured in adults using specific RIA after extraction with acid-ammonium sulfate. Mean (+/- SD) total urine IGF-I values were 267.9 +/- 112.9 ng/day and 167.8 +/- 73.2 ng/g creatinine (Cr) in 17 normal young adults. There was a positive correlation (r = 0.785, P < 0.001) between IGF-I values in early morning urine and those of 24 h urine when they were corrected by urinary Cr. IGF-I values in early morning urine were ranged from 60 to 1,100 ng/gCr with a mean value of 309.6 ng/gCr in 178 normal adults aged 21-80 yr. There was a consistent trend towards higher urinary IGF-I values in males during aging and this trend did not reach statistical significance until the sixth and seventh decades. There was a positive correlation (r = 0.465, P < 0.005) between urinary IGF-I values and age in males but not in females. Although urinary IGF-I values were higher in females than in males of the second and third decades, no sex difference was found in older adults. Urinary IGF-I values were correlated reversely with 24 h Cr clearance (CCr) and positively with urinary beta 2-microglobulin (beta 2-MG) levels in patients with renal dysfunction. These findings indicate that urinary IGF-I levels are influenced by age, sex and renal function in adults.  相似文献   

3.
The objectives of this study were to examine the association between urinary excretion of cadmium (U-Cd), copper (U-Cu), and zinc (U-Zn) and the severity of two different indicators of renal toxicity (urinary excretion of beta2-microglobulin [U-beta2-MG] and metallothionein [U-MT]) in Cd-exposed subjects compared to controls, and to assess the physiologic mechanisms by which the exposure to environmental Cd affects U-Cd, U-Cu, and U-Zn. The target population included 3508 Cd-exposed and 294 nonexposed participants who received a health survey conducted among the population of the Kakehashi River basin. Increases of U-Cd, U-beta2-MG, and U-MT in the Cd-exposed population were observed relative to excretion of these substances in controls. Regression analysis using a general linear model revealed that the correlations between U-Cd or U-Cu, and U-beta2-MG and between U-Cd, U-Cu or U-Zn, and U-MT were statistically significant in both sexes, but the correlation between U-Zn and U-beta2-MG excretion was significant only in men. These results suggest U-Cd and U-Cu is affected by dysfunction in renal tubular absorption (indicated by U-beta2-MG), whereas not only U-Cd and U-Cu but also U-Zn appear to be a function of renal cellular desquamation (indicated by U-MT).  相似文献   

4.
Bone damage caused by exposure to cadmium (Cd) is often seen in Cd-polluted areas, and increased excretion of calcium (Ca) in urine is thought to be an important factor affecting bone damage. In order to clarify the significance of urinary Ca excretion in bone damage, we investigated the urinary excretion levels of Ca and phosphorus (P) of inhabitants of a Cd-polluted area and compared them to those of nonexposed subjects, and explored the possible association between urinary Ca or P and β 2-microglobulin (β 2-MG). The target subjects were 3164 inhabitants of the Cd-polluted Kakehashi River basin. Ca and Ca/P measurements were significantly higher in the Cd-polluted area than in the controls. In multiple-regression analysis, where either Ca or P was used as the criterion variable, and age, Cd, and β 2-MG were used as explanatory variables, there were positive associations between Ca and Cd and β 2-MG in both sexes. Therefore, the increased excretion level of Ca was the result of renal dysfunction. Bone damage is not thought to be caused by increased excretion of Ca alone because urinary excretion levels of Ca do not differ greatly between people with and without bone damage.  相似文献   

5.
Low levels of high density lipoprotein cholesterol (HDL-C) are associated with increased risk of coronary heart disease and, in the United States, are often associated with hypertriglyceridemia and obesity. In Turkey, low HDL-C levels are highly prevalent, 53% of men and 26% of women having HDL-C levels <35 mg/dl, in the absence of hypertriglyceridemia and obesity. In this study to investigate the cause of low HDL-C levels in Turks, various factors affecting HDL metabolism were assessed in normotriglyceridemic Turkish men and women living in Istanbul and in non-Turkish men and women living in San Francisco. Turkish men and women had significantly lower HDL-C levels than the San Francisco men and women, as well as markedly lower apolipoprotein A-I levels (25 and 39 mg/dl lower, respectively). In both Turkish and non-Turkish subjects, the mean body mass index was <27 kg/m2, the mean triglyceride level was <120 mg/dl, and the mean total cholesterol was 170-180 mg/dl. The mean hepatic triglyceride lipase activity was 21% and 31% higher in Turkish men and women, respectively, than in non-Turkish men and women, and remained higher even after subjects with a body mass index >50th percentile for men and women in the United States were excluded from the analysis. As no dietary or behavioral factors have been identified in the Turkish population that account for increased hepatic triglyceride lipase activity, the elevation most likely has a genetic basis. high density lipoprotein in a normotriglyceridemic, nonobese Turkish population.  相似文献   

6.
The usefulness of spot determination of urinary cortisol in the screening of Cushing's syndrome was evaluated by measuring the cortisol concentration in randomly sampled urine in 68 normal subjects and in 9 patients with Cushing's syndrome. The urinary cortisol concentration in the morning was significantly higher in patients with Cushing's syndrome but some overlap existed between normal subjects and patients with Cushing's syndrome. In contrast, there was a clear discrimination between two groups when urinary cortisol was measured in the late evening: urinary cortisol was lower than 75 micrograms per gram creatinine (microgram/gCr) in normal subjects but higher than 150 micrograms/gCr in patients with Cushing's syndrome. When 1 mg dexamethasone was administered at 2300 h in the evening, spot urinary cortisol the next morning was less than 80 micrograms/gCr in normal subjects while it was above 100 micrograms/gCr in patients with Cushing's syndrome. Dexamethasone-induced suppression of urinary cortisol in normal subjects lasted until late in the afternoon, which allows sampling of urine at any time in the morning and possibly in the afternoon. These results suggest the usefulness of spot determination of urinary cortisol in the screening of Cushings' syndrome.  相似文献   

7.

Objective

Our aim was to investigate whether trends in quality of diabetes care differ between sexes in the Netherlands from 1998 till 2013.

Research Design and Methods

In this prospective observational cohort study quality of care was measured using process and outcome measures in patients with type 2 diabetes in primary care. Trend and absolute differences between sexes were investigated for patients <75 years. Subgroup analyses were performed in patients ≥75 years. 10-year mortality risk was assessed with the Globorisk risk equation in patients without cardiovascular diseases <75 years.

Results

The number of patients increased from 2,644 in 1998 to 62,230 in 2013. In 1998, 51% of the men and 60% of the women <75 years had an HbA1c >53 mmol/mol; this decreased to approximately 29% in both sexes in 2013. Patients having a systolic blood pressure >140 mmHg decreased from 70% to 42%, and from 80% to 40% in men and women <75 years, respectively. In patients ≥75 years it decreased from 72% to 50% in men and 85% to 56% in women. Obesity increased in both sexes, whereas smoking in men and women declined in patients <75 years (men: 34% to 22%; women: 22% to 18%). The number of patients with a mortality risk >20% over 10 years decreased from 15% to 3% in men and from 18% to 3% in women.

Conclusions

Quality of diabetes care has improved considerably in the period 1998–2013 in both sexes. Possibly relevant trend differences between sexes were observed for HbA1c, systolic blood pressure, BMI and smoking. The predicted mortality risk decreased over time in both sexes. Except for BMI in both age groups and systolic blood pressure in patients ≥75 years, no evident poorer risk factor control in women compared to men was found at the end of the study period.  相似文献   

8.
Adipose tissue lipolytic activity is increased in endurance-trained subjects, but little is known about the mechanisms of this increase. To understand more fully the mechanisms involved and to discover whether sex-related differences exist, biopsies of fat were performed in the periumbilical region of 20 sedentary subjects (10 women (W) and 10 men (M)) and 20 trained subjects (10 W, 10 M); the in vitro response to epinephrine of the collagenase-isolated fat cells was studied. Glycerol release, chosen as an adipocyte lipolysis indicator, was measured by bioluminescence. Dose-response curves with epinephrine (alpha 2 and beta agonist), with isoproterenol (beta agonist) and epinephrine + propranolol and adenosine deaminase, were studied. Epinephrine-induced lipolysis was enhanced in trained subjects and this was due to an increased efficiency of the beta-adrenergic pathway. However, differences were found between the two sexes. In trained men, the lipolysis increase resulted from the enhancement of the beta-adrenergic pathway efficiency without any significant decrease in the alpha 2-adrenergic pathway efficiency. In trained women, the lipolysis increase was not only due to the enhancement of the beta-adrenergic pathway efficiency (which was greater than in trained men), but also to a significant decrease in the alpha 2-adrenergic pathway efficiency. Despite the decrease, the alpha 2-adrenergic pathway remained more efficient in trained women than in trained men, as was the case in sedentary subjects. It is concluded that endurance training led to better lipid mobilization and that this effect seemed greater in women than in men.  相似文献   

9.
An 18-day experiment was conducted to investigate the uptake and sublethal toxicity of dietary Ni in adult lake whitefish (LWF, Coregonus clupeaformis) and lake trout (LT, Salvelinus namaycush) fed diets containing 0, 1000 and 10000 microg Ni/g, prepared with and without brine shrimp. The results of this experiment were used to design an experiment of longer duration in which one of the fish species was selected and exposed to lower dietary Ni doses. In the present study feed refusal was observed in LT and LWF fed 10000 microg Ni/g, after three and 4-5 feedings, respectively. LT fed Ni-contaminated diets exhibited different patterns of Ni accumulation than LWF. Increased Ni concentrations in all LWF tissues, except the intestine, were associated with increased doses of Ni. Copper and Zn concentrations in kidney and liver of LWF were altered. Metallothionein concentrations in kidneys of LT fed 1000 microg Ni/g and 10000 microg Ni/g and LWF fed 10000 microg Ni/g and in livers of LWF fed 10000 microg Ni/g (diet without shrimp only) increased significantly. Increased lipid peroxide production in the plasma of LT fed 10000 microg Ni/g was observed. Blood glucose and electrolytes were affected by Ni exposure. Histopathological alterations were observed in kidneys of LWF fed low and high dose diets, livers of whitefish fed high dose diets, and intestines of LWF fed high dose diets and LT fed low and high dose diets. LT fed high dose diets exhibited significant decreases in weight.  相似文献   

10.
The lipids and lipoproteins — cholesterol (C), triglyceride (TG) and high-density, low-density, very-low-density and sinking pre-β-lipoprotein cholesterol (HDL-C, LDL-C, VLDL-C and SPB-C) — in plasma samples from 1620 fasting white adults and children from the Toronto—Hamilton area were analysed. The mean concentration of HDL-C was about 45 mg/dl in men and about 60 mg/dl in women, and the levels were constant throughout adult life in both sexes. Boys had higher mean HDL-C levels than men, but girls had lower mean HDL-C levels than women. Mean LDL-C levels, like total C levels, increased with age, from about 87 mg/dl in boys to 136 mg/dl in men, and from about 91 mg/dl in girls to 145 mg/dl in women. The mean levels of VLDL-C followed the TG patterns for age and sex, rising from about 7 mg/dl in boys to 26 mg/dl in men, and from about 11 mg/dl in girls to 19 mg/dl in women. SPB-C was detectable visually in 39% of the population and with the aid of densitometry in 54%; the levels were not related to age, sex or oral contraceptive use, and the median level was 3 mg/dl.Prevalence estimates of hyperlipoproteinemia showed that type IV was the most common, and it was found more than three times as often in men as in women. This was in part due to the customary use of plasma TG cut-off points that do not reflect the large difference in TG levels between males and females. Type IIA hyperlipoproteinemia was found in about 2% of the adults and type IIb in a further 1%. Types I, III and V were all rare. The prevalence of types II and IV hyperlipoproteinemia was four times greater in women using oral contraceptives than in nonusers in the same age range.  相似文献   

11.
Increased incidence of orthostatic hypotension and presyncopal symptoms in young women could be related to hormonal factors that might be isolated by comparing cardiovascular and cerebrovascular responses to postural change in young and older men and women. Seven young women, 11 young men, 10 older women (>1 yr postmenopausal, no hormone therapy), and 9 older men participated in a supine-to-sit-to-stand test while measuring systemic hemodynamics, end-tidal Pco(2), and blood flow velocity of the middle cerebral artery (MCA). Women had a greater reduction in stroke volume index compared with age-matched men (change from supine to standing: young women: -22.9 ± 1.6 ml/m(2); young men: -14.4 ± 2.4 ml/m(2); older women: -17.4 ± 3.3 ml/m(2); older men: -13.8 ± 2.2 ml/m(2)). This was accompanied by offsetting changes in heart rate, particularly in young women, resulting in no age or sex differences in cardiac output index. Mean arterial pressure (MAP) was higher in older subjects and increased with movement to upright postures. Younger men and women had higher forearm vascular resistance that increased progressively in the upright posture compared with older men and women. There was no difference between sexes or ages in total peripheral resistance index. Women had higher MCA velocity, but both sexes had reduced MCA velocity while upright, which was a function of reduced blood pressure at the MCA and a significant reduction in end-tidal Pco(2). The reductions in stroke volume index suggested impaired venous return in women, but augmented responses of heart rate and forearm vascular resistance protected MAP in younger women. Overall, these results showed significant sex and age-related differences, but compensatory mechanisms preserved MAP and MCA velocity in young women.  相似文献   

12.

Background

Waist circumference (WC) adjusted for body mass index (BMI) is positively associated with mortality, but the association with changes in WC is less clear. We investigated the association between changes in WC and mortality in middle-aged men and women, and evaluated the influence from concurrent changes in BMI.

Methodology/Principal Findings

Data on 26,625 healthy men and women from the Danish Diet, Cancer and Health study was analyzed. WC and BMI were assessed in 1993–97 and in 1999–02. Information on mortality was obtained by linkage to the Danish central Person Register. Hazard ratios (HR) were estimated with Cox regression models. During 6.7 years of follow-up, 568 and 361 deaths occurred among men and women, respectively. Changes in WC were positively associated with mortality (HR per 5 cm for the sexes combined  = 1.09 (1.02∶1.16) with adjustment for covariates, baseline WC, BMI and changes in BMI), whereas changes in BMI were inversely associated with mortality (HR per kg/m2 for the sexes combined  = 0.91 (0.86, 0.97) with adjustment for covariates, baseline WC, BMI and changes in WC). Associations between changes in WC and mortality were not notably different in sub-groups stratified according to changes in BMI, baseline WC or when smokers or deaths occurring within the first years of follow-up were excluded.

Conclusions/Significance

Changes in WC were positively associated with mortality in healthy middle-aged men and women throughout the range of concurrent changes in BMI. These findings suggest a need for development of prevention and treatment strategies targeted against redistribution of fat mass towards the abdominal region.  相似文献   

13.
The aim of this study was to evaluate the effect of ethylenediaminetetraacetic acid (EDTA) on cadmium (Cd) induced renal dysfunction. Seventeen workers (14 males, 3 females) were diagnosed with occupational Cd poisoning in 1986. These individuals had between 7 to 39 years of Cd exposure. From 1986 to 1999, patients received periodic EDTA therapy as part of their follow-up, all at the same hospital. Levels of urinary cadmium (UCd) and urinary beta2-microglobulin (B2M) were measured before and after each annual EDTA treatment period. Renal dysfunction was defined as urinary B2M > 0.8 mg/g Cr (creatinine). In these workers, patients with UCd level higher than 10 microg/g Cr in 1986 had abnormal B2M excretions (> or = 0.8 mg/g Cr) or trended to have abnormal B2M levels during the treatment period. However, in subjects with UCd concentration lower than 10 microg/g Cr in 1986, their urinary B2M excretions either remained normal (< 0.8 mg/g Cr) or returned to normal during the treatment period. The prevalence of renal dysfunction increased during the follow up period regardless of whether UCd levels increased or not, indicating a progressive renal dysfunction despite removal from Cd exposure. Our results suggest that reversibility of renal dysfunction caused by Cd related to the level of Cd exposure at the time of removal from exposure: renal dysfunction could be reversed if initial UCd < 10 microg/g Cr, but was irreversible when UCd > 10 microg/g Cr. Repeated examinations on these 17 Cd exposed workers from 1986 to 1999 also revealed that periodic administration of EDTA had no beneficial effects on chronic Cd-induced renal dysfunction.  相似文献   

14.
Apolipoprotein E (apoE) and lipoprotein cholesterol and triglycerides were measured in blood serum of 272 persons randomly selected from a large industrial population in northern California. Serum apoE level increased linearly by 0.013 mg/dl with each 1 mg/dl increase in very low density lipoprotein (VLDL) triglycerides. This estimate was independent of sex and the use of sex hormones by women. Compositional studies of isolated apoVLDL in 156 hypertriglyceridemic men and 162 normotriglyceridemic persons of both sexes from the same population also indicated that the content of apoE was independent of VLDL level, sex, and hormone use. The estimate of the relationship between serum apoE and VLDL-triglycerides derived from these compositional studies was comparable to that derived by regression analysis. Regression analysis also indicated that only 10-20% of the apoE in the serum of the average person is in the VLDL fraction. Serum apoE levels were 1.4 mg/dl higher in women than in men with the same VLDL-triglyceride level and 1.8 mg/dl lower in women using contraceptive drugs than in nonusers of like age and VLDL-triglyceride level.  相似文献   

15.
There is growing evidence that oxidative stress contributes to the pathogenesis of hypertension. Our aim was to measure markers of oxidative stress in hypertensive subjects, and assess the potential confounding influences of antihypertensive therapy, other cardiovascular risk factors, gender, lifestyle, and nutrition. Markers of oxidative stress, including plasma and 24 h urinary F2-isoprostanes, were measured in 70 untreated (men = 43, women = 27) and 85 treated (men = 43, women = 42) hypertensive subjects and 40 normotensive controls (men = 20, women = 20). Overall, F2-isoprostanes were not elevated in hypertensive subjects compared with controls. However, urinary and plasma F2-isoprostanes were significantly lower in treated compared with untreated hypertensive men, but not women. In hypertensive men, the number of antihypertensive drugs taken was inversely associated with both urinary and plasma F2-isoprostanes (p <.05). Self-reported alcohol intake and biomarkers of alcohol consumption (gamma-glutamyl transpeptidase and high-density lipoprotein cholesterol) were positively associated with plasma but not urinary, F2-isoprostanes in men. Several nutrients were independently associated with plasma and urinary F2-isoprostanes in women. The results do not support the hypothesis that treated or untreated hypertensive subjects are under increased oxidative stress compared with normotensive controls.  相似文献   

16.
The purpose of the study was to examine the validity of alpha1-microglobulin (alpha1-MG) in comparison with popularly used beta2-microglobulin (beta2-MG). A database was revisited to select ca. 7,500 spot urine samples (of adequate urine density) from non-pregnant, non-lactating and never-smoking adult women. The validity of the MGs was examined in terms of stability of the MG-uria prevalence in urine samples of various creatinine (CR or cr) concentration or specific gravity (SG or sg). Comparisons were made for MGs as observed (e.g., alpha1-MGob), as corrected for CR (e.g., alpha1-MGcr) and as corrected for SG of 1.016 (e.g., alpha1-MGsg). A cut-off value of 5.7 mg/g cr (or mg/l) for alpha1-MG was deduced from a cut-off value of 400 microg/g cr (or mcirog/l) for beta2-MG, because the correlation between alpha1-MGcr and beta2-MGcr was statistically significant. The prevalence of a 1-MGsg-uria was essentially unchanged (i.e., from a low of 13.6% to a high of 17.0%, or 1.2 times) except for in very dense or very thin urine samples, in contrast, beta2-MGcr-uria showed a substantial increase (from 0.0% to 2.8% with an infinite rate) as a reverse function of a decrease in CR in urine. The prevalence of uncorrected markers, i.e., alpha1-MGob-uria and beta2-MGob-uria, showed even greater CR- or SG-dependent changes. Thus, it appeared prudent to consider a alpha-MGsg rather than beta2-MGcr as a marker of tubular dysfunction among a general population with various urine density.  相似文献   

17.

Background

Counties are the smallest unit for which mortality data are routinely available, allowing consistent and comparable long-term analysis of trends in health disparities. Average life expectancy has steadily increased in the United States but there is limited information on long-term mortality trends in the US counties This study aimed to investigate trends in county mortality and cross-county mortality disparities, including the contributions of specific diseases to county level mortality trends.

Methods and Findings

We used mortality statistics (from the National Center for Health Statistics [NCHS]) and population (from the US Census) to estimate sex-specific life expectancy for US counties for every year between 1961 and 1999. Data for analyses in subsequent years were not provided to us by the NCHS. We calculated different metrics of cross-county mortality disparity, and also grouped counties on the basis of whether their mortality changed favorably or unfavorably relative to the national average. We estimated the probability of death from specific diseases for counties with above- or below-average mortality performance. We simulated the effect of cross-county migration on each county''s life expectancy using a time-based simulation model. Between 1961 and 1999, the standard deviation (SD) of life expectancy across US counties was at its lowest in 1983, at 1.9 and 1.4 y for men and women, respectively. Cross-county life expectancy SD increased to 2.3 and 1.7 y in 1999. Between 1961 and 1983 no counties had a statistically significant increase in mortality; the major cause of mortality decline for both sexes was reduction in cardiovascular mortality. From 1983 to 1999, life expectancy declined significantly in 11 counties for men (by 1.3 y) and in 180 counties for women (by 1.3 y); another 48 (men) and 783 (women) counties had nonsignificant life expectancy decline. Life expectancy decline in both sexes was caused by increased mortality from lung cancer, chronic obstructive pulmonary disease (COPD), diabetes, and a range of other noncommunicable diseases, which were no longer compensated for by the decline in cardiovascular mortality. Higher HIV/AIDS and homicide deaths also contributed substantially to life expectancy decline for men, but not for women. Alternative specifications of the effects of migration showed that the rise in cross-county life expectancy SD was unlikely to be caused by migration.

Conclusions

There was a steady increase in mortality inequality across the US counties between 1983 and 1999, resulting from stagnation or increase in mortality among the worst-off segment of the population. Female mortality increased in a large number of counties, primarily because of chronic diseases related to smoking, overweight and obesity, and high blood pressure.  相似文献   

18.
During the course of two years, 76 representative subjects seen in a community hospital emergency room who admitted to having recently used alcohol while still appearing sober had their blood alcohol levels measured to determine the levels of blood alcohol present in ambulatory sober alcohol users. As a group the mean blood alcohol level obtained in those who had measurable levels was 268 ± 10 mg/dl mean ± SEM). More men (47) than women (18) admitted to having used ethanol and had measurable blood ethanol levels and therefore were studied. Moreover, the mean blood alcohol level in the men studied was arithmetically greater (272 ± 13 mg/d1) than that present in the women (260 ± 13mg/d1). The range of alcohol levels seen in the two sexes, however, were quite similar. Using a blood alcohol level > 200 mg/dl in a clinically “non-intoxicated” individual as the cut-off level for defining one as a suspect chronic alcohol user, our data would suggest that such individuals not uncommonly have blood alcohol levels as high as 290 ± 9 mg/dl.  相似文献   

19.
The aims of this study were 1) to determine whether differential glycemic thresholds are the mechanism responsible for the sexual dimorphism present in neuroendocrine responses during hypoglycemia and 2) to define the differences in counterregulatory physiological responses that occur over a range of mild to moderate hypoglycemia in healthy men and women. Fifteen (8 male, 7 female) lean healthy adults underwent four separate randomized 2-h hyperinsulinemic (1.5 mU. kg(-1).min(-1)) glucose clamp studies at euglycemia (90 mg/dl) or hypoglycemia of 70, 60, or 50 mg/dl. Plasma insulin levels were similar during euglycemic and hypoglycemic studies (91-96 +/- 8 microU/ml) in men and women. Hypoglycemia of 70, 60, and 50 mg/dl all resulted in significant increases (P < 0.05, P < 0.01) in epinephrine, glucagon, growth hormone, cortisol, and pancreatic polypeptide levels compared with euglycemic studies in men and women. Plasma norepinephrine levels were increased (P < 0.05) only relative to euglycemic studies at a hypoglycemia of 50 mg/dl. Muscle sympathetic nerve activity (MSNA) increased significantly during hyperinsulinemic-euglycemic control studies. Further elevations of MSNA did not occur until hypoglycemia of 60 mg/dl in both men and women. Plasma epinephrine, glucagon, growth hormone, and pancreatic polypeptide were significantly increased in men compared with women during hypoglycemia of 70, 60, and 50 mg/dl. MSNA, heart rate, and systolic blood pressure responses were also significantly increased in men at hypoglycemia of 60 and 50 mg/dl. In summary, these studies have demonstrated that, in healthy men and women, the glycemic thresholds for activation of epinephrine, glucagon, growth hormone, cortisol, and pancreatic polypeptide occur between 70 and 79 mg/dl. Thresholds for activation of MSNA occur between 60 and 69 mg/dl, whereas norepinephrine is not activated until glycemia is between 50 and 59 mg/dl. We conclude that 1) differential glycemic thresholds are not the cause of the sexual dimorphism present in counterregulatory responses to hypoglycemia; 2) reduced central nervous system efferent input appears to be the mechanism responsible for lowered neuroendocrine responses to hypoglycemia in women; and 3) physiological counterregulatory responses (neuroendocrine, cardiovascular, and autonomic nervous system) are reduced across a broad range of hypoglycemia in healthy women compared with healthy men.  相似文献   

20.
Results of studies comparing overall obesity and abdominal adiposity or body fat distribution with risk of mortality have varied considerably. We compared the relative importance and joint association of overall obesity and body fat distribution in predicting risk of mortality. Participants included 5,799 men and 6,429 women aged 30–102 years enrolled in the third National Health and Nutrition Examination Survey who completed a baseline health examination during 1988–1994. During a 12‐year follow‐up (102,172 person‐years), 1,188 men and 925 women died. In multivariable‐adjusted analyses, waist‐to‐thigh ratio (WTR) in both sexes (Ptrend <0.01 for both) and waist‐to‐hip ratio (WHR) in women (Ptrend 0.001) were positively associated with mortality in middle‐aged adults (30–64 years), while BMI and waist circumference (WC) exhibited U‐ or J‐shaped associations. Risk of mortality increased with a higher WHR and WTR among normal weight (BMI 18.5–24.9 kg/m2) and obese (BMI ≥30.0 kg/m2) adults. In older adults (65–102 years), a higher BMI in both sexes (Ptrend <0.05) and WC in men (Ptrend 0.001) were associated with increased survival, while remaining measures of body fat distribution exhibited either no association or an inverse relation with mortality. In conclusion, ratio measures of body fat distribution are strongly and positively associated with mortality and offer additional prognostic information beyond BMI and WC in middle‐aged adults. A higher BMI in both sexes and WC in men were associated with increased survival in older adults, while a higher WHR or WTR either decreased or did not influence risk of death.  相似文献   

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