Health and motivation as mediators of the effects of job demands, job control, job support, and role conflicts at work and home on sickness presenteeism and absenteeism.

PURPOSE: The first objective was to contribute to a better understanding of the contrasting and paradoxical results in studies of work environment factors and sickness presence and sickness absence. A second objective was to examine if, and under what conditions, employees choose to replace sickness absence with sickness presence, i.e., so-called substitution. METHODS: The study utilizes a large body of cross-sectional questionnaire data (n = 130,161) gathered in Sweden from 2002 to 2007 in connection with a comprehensive health promotion initiative. Health and motivation were analyzed as mediators of the effects of five job factors, job control, job support, job demand, role conflict and "work to family conflict" on sickness presence and absence. RESULTS: The results concerning job demands indicate substitution in that increased job demands are associated with increased presenteeism and reduced absenteeism. The direct effect of higher job support was increased absenteeism, but via the health and motivation paths, the total effect of more social support was health-promoting and associated with a reduction in sickness absence and sickness presence. High job control emerged as the most pronounced health-promoting factor, reducing sickness presenteeism as well as absenteeism. More role conflicts and work-to-family conflicts were directly and indirectly associated with decreased health and increased absenteeism as well as presenteeism. earlier research. CONCLUSION: The mediation analyzes shed light on some of the paradoxes in research on sickness presenteeism and sickness absenteeism, especially regarding job demands and job support. The substitution effect is important for workplace policy and occupational health practice.

Cardiorespiratory Fitness and Metabolic Syndrome in Postmenopausal African-American Women.

We examined the association of cardiorespiratory fitness with metabolic syndrome in overweight/obese postmenopausal African-American women. Pooled baseline data on 170 African-American women from 2 exercise trials were examined. Metabolic syndrome was defined as at least 3 of the following: abdominal obesity, glucose intolerance, hypertension, low high-density lipoprotein cholesterol (HDL-C), and high triglycerides. Cardiorespiratory fitness (VO2peak) was determined using the Bruce treadmill protocol and categorized as: Very Low (VLCRF<18 mL·kg(-1) min(-1)), Low (LCRF=18.0-220-22-22.0 mL·kg(-1) min(-1)), and Moderate (MCRF>22.0 mL·kg(-1) min(-1)). Associations of metabolic syndrome with cardiorespiratory fitness were analyzed using one-way ANOVA and linear regression. VO2peak was significantly lower in the VLCRF compared to the MCRF group. Lower cardiorespiratory fitness was associated with higher prevalence of metabolic syndrome, abdominal obesity, hypertriglyceridemia, and low HDL among overweight/obese postmenopausal African-American women. In fully adjusted models, higher waist circumference and triglycerides were associated with lower VO2peak levels (P<0.01) and higher HDL-C was associated with higher VO2peak levels (P=0.03). Overweight/obese postmenopausal African-American women with very low cardiorespiratory fitness are more likely to have metabolic syndrome, higher body mass index, and unhealthier levels of certain metabolic syndrome components than women with moderate cardiorespiratory fitness.

Validity and test-retest reliability of an at-work production loss instrument.

BACKGROUND: Besides causing ill health, a poor work environment may contribute to production loss. Production loss assessment instruments emphasize health-related consequences but there is no instrument to measure reduced work performance related to the work environment. AIMS: To examine convergent validity and test-retest reliability of health-related production loss (HRPL) and work environment-related production loss (WRPL) against a valid comparable instrument, the Health and Work Performance Questionnaire (HPQ). METHODS: Cross-sectional study of employees, not on sick leave, who were asked to self-rate their work performance and production losses. Using the Pearson correlation and Bland and Altman's Test of Agreement, convergent validity was examined. Subgroup analyses were performed for employees recording problem-specific reduced work performance. Consistency of pairs of HRPL and WRPL for samples responding to both assessments was expressed using Intraclass Correlation Coefficient (ICC) and tests of repeatability. RESULTS: A total of 88 employees participated and 44 responded to both assessments. Test of agreement between measurements estimates a mean difference of 0.34 for HRPL and -0.03 for WRPL compared with work performance. This indicates that the production loss questions are valid and moderately associated with work performance for the total sample and subgroups. ICC for paired HRPL assessments was 0.90 and 0.91 for WRPL, i.e. the test-retest reliability was good and suggests stability in the instrument. CONCLUSIONS: HRPL and WRPL can be used to measure production loss due to health-related and work environment-related problems. These results may have implications for advancing methods of assessing production loss, which represents an important cost to employers.

Swedish translation and validation of a web-based questionnaire for registration of overuse problems.

The main aim of this study was to translate the Oslo Sport Trauma Research Center (OSTRC) Overuse Injury Questionnaire into Swedish. The validity and applicability of the questionnaire for studying overuse injuries among Swedish handball, volleyball, tennis, and orienteering top athletes were also examined. The back-translation method was used for translation. An expert committee further developed it for use in a study of injuries in handball, orienteering, tennis, and volleyball. A 10-week pretest was then conducted on 43 athletes, average age 21 (18-31) from these sports, during which time the athletes completed the modified OSTRC questionnaire on a weekly basis. In the 10th week, four additional questions were added in order to examine the questionnaire's content validity. No major disagreement was found in the translation. The athletes perceived the web-based questionnaire to be smooth and easy to complete, accurately capturing overuse injuries. However, suggestions were made to add questions relating to the hip for orienteerers and to the hand/fingers for handball players. The average prevalence of overuse injuries for all athletes, in any anatomical area was 22% (95% confidence interval 20-25). Construct validity appeared to be high, and we therefore suggest that the questionnaire may be used when studying overuse injuries in different sports.

Relationships among changes in C-reactive protein and cardiovascular disease risk factors with lifestyle interventions.

BACKGROUND AND AIMS: Inflammation plays a role in the development of cardiovascular disease (CVD). Elevated levels of the inflammatory marker, C-reactive protein (CRP), are cross-sectionally associated with traditional CVD risk factors and are being considered as an emerging CVD risk factor. In a secondary data analysis, we examined changes in CRP and several CVD risk factors after one-year diet and physical activity interventions to assess whether CRP changed concurrently with other risk factors, or was independent of the traditional risk factors. METHODS AND RESULTS: Data were analyzed from 143 men and 133 women with dyslipidemia who were randomized to one-year interventions of low-fat diet only, physical activity only, diet plus physical activity, or control. Plasma high-sensitivity CRP, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides (TG), fasting and 2-hr blood glucose and insulin, blood pressure (BP), and waist circumference were obtained at baseline and follow-up. Multiple linear regression models were used to predict CRP change based on other risk factor changes, controlling for age, race, alcohol intake, and hormone replacement therapy. Treatment groups were combined for analysis. Baseline mean (SD) CRP levels were 1.3 ± 1.3 (men) and 1.9 ± 1.8 mg/L (women), with mean changes of -0.11 ± 1.3 and -0.17 ± 1.5 mg/L, respectively. Plasma CRP change was negatively associated with TG change in men (p = 0.003) and women (p = 0.05), positively associated with change in systolic BP in men (p = 0.01), but was not associated with changes in the other risk factors. CONCLUSION: Dietary and/or physical activity induced changes in CRP may be largely independent of traditional CVD risk factors in persons with dyslipidemia.

The impact of bystanding to workplace bullying on symptoms of depression among women and men in industry in Sweden: an empirical and theoretical longitudinal study.

BACKGROUND: Prospective studies on bystanding to workplace bullying and the health outcomes are scarce. AIM: To investigate the work environmental risk factors of depressive symptoms among bystanders to bullying in both women and men in four large industrial organizations in Sweden. METHOD: The number of respondents at four large industrial enterprises with more than one year at the workplace at T1: n = 2,563 (Women: n = 342; Men: n = 2,227). Bystanders to bullying at T1: n = 305 (Women: n = 30; Men: n = 275). The total number of those with symptoms of depression at T2: Women: n = 30; Men: n = 161. Two thousand one hundred and seventy-seven employees answered the questionnaire on T1 and T2 with an 18-month interval. "To have depressive symptoms" was defined as not having depressive symptoms at T1 but having depressive symptoms at T2. RESULTS: The number of men who were bystanders to bullying was larger compared to women. However, the proportion of women who were bystanders to bullying and developed depressive symptoms 18 months later was higher in comparison with men (33.3 and 16.4 %, respectively). Further, "Being a bystander to bullying" 1.69 (1.13-2.53), "Rumors of changes in the workplace" 1.53 (1.10-2.14), "Reduced role clarity" 2.30 (1.21-4.32), "Lack of appreciation of being in the group" 1.76 (1.22-2.53) increased the risk of future symptoms of depression. "Job Strain" was not an adjusted risk factor for depression. CONCLUSION: Our results support previous findings that bystanding to workplace bullying is related to future depressive symptoms.

The effects of aerobic training and age on plasma sICAM-1.

Chronic low-grade systemic inflammation plays a role in the development of cardiovascular (CV) disease. Habitual endurance exercise training reduces the risk of CV disease in part through anti-inflammatory mechanisms. The purpose of this study was to investigate the effects of age, endurance training status, and their interaction on pro-inflammatory plasma cytokines involved in the pathogenesis of CV disease. Subjects were BMI-matched young (25±3 years; endurance trained: n=9, sedentary: n=11) and older (62±5 years; endurance-trained: n=12, sedentary: n=11) men. Plasma cytokine concentrations were determined by multiplex cytometric bead assay. Soluble intercellular adhesion molecule-1 (sICAM-1) levels were 40% higher in sedentary older men compared to young sedentary subjects (P=0.048), but they were not different between the young and older trained men. Furthermore, sICAM-1 levels were negatively correlated with maximal oxygen uptake (V˙O2max; r= - 0.38, P=0.01) across all subjects. There were no significant differences among the groups in plasma concentrations of monocyte chemoattractant protein-1 (MCP-1), soluble tumor necrosis-α receptor (sTNFR), soluble CD40 ligand (sCD40L), or resistin. We conclude that habitual endurance training is associated with an attenuated age-related increase in plasma sICAM-1.

Nitro-oxidative stress biomarkers in active and inactive men.

Oxidative stress markers are novel factors shown to be related to cardiovascular (CVD) risk. We examined the effects of long-term exercise, age, and their interaction on plasma oxidized LDL (ox-LDL), nitrotyrosine, and myeloperoxidase (MPO) levels, all biomarkers of oxidative stress, and determined their association with plasma nitric oxide (NOx) levels as an index of NO bioavailability. Older (62±2 yr) active men (n=12) who had exercised for >30 years and young (25±4 yr) active men (n=7) who had exercised for >3 years were age- and BMI-matched to older (n=11) and young (n=8) inactive men. Young subjects had lower plasma nitrotyrosine levels than older subjects (P=0.047). Young inactive subjects had higher ox-LDL levels than either the young active (P=0.042) or the older active (P=0.041) subjects. In addition, plasma oxidative stress levels, particularly ox-LDL, were correlated with various conventional plasma lipoprotein-lipid levels, and in older subjects were associated with Framingham risk score (r=0.49, P=0.015). We found no relationships between plasma oxidative stress markers and NOx levels. The findings suggest that a sedentary lifestyle may be associated with higher ox-LDL levels and that the levels of oxidative stress markers are related to levels of other conventional CVD risk factors and overall CVD risk.

Effects of endurance exercise training on markers of cholesterol absorption and synthesis.

Abnormal cholesterol metabolism, including low intestinal cholesterol absorption and elevated synthesis, is prevalent in diabetes, obesity, hyperlipidemia, and the metabolic syndrome. Diet-induced weight loss improves cholesterol absorption in these populations, but it is not known if endurance exercise training also improves cholesterol homeostasis. To examine this, we measured circulating levels of campesterol, sitosterol, and lathosterol in 65 sedentary subjects (average age 59 years; with at least one metabolic syndrome risk factor) before and after 6 months of endurance exercise training. Campesterol and sitosterol are plant sterols that correlate with intestinal cholesterol absorption, while lathosterol is a marker of whole body cholesterol synthesis. Following the intervention, plant sterol levels were increased by 10% (p<0.05), but there was no change in plasma lathosterol. In addition, total and LDL-cholesterol were reduced by 0.16 mmol and 0.10 mmol, respectively (p<0.05), while HDL-C levels increased by 0.09 mmol (p<0.05). Furthermore, the change in plant sterols was positively correlated with the change in VO2max (r=0.310, p=0.004), independent of other metabolic syndrome risk factors. These data indicate that exercise training reduces plasma cholesterol despite increasing cholesterol absorption in subjects with metabolic syndrome risk factors.

Occurrence of polybrominated dibenzo-p-dioxins, dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs) in pilot whales (Globicephala melas) caught around the Faroe Islands.

Blubber from Faroese pilot whales (Globicephala melas) was analysed for brominated dioxins PBDD/Fs, with a subset also analysed for chlorinated dioxins, PCDD/Fs. The studied individuals were restricted to juvenile male whales sampled in the Faroe Islands during the period 1997-2013. Among the PBDD/Fs, the furans were predominant, although the relative abundance of various congeners differed between samples. Furans accounted for, on average, 79% of the ∑PBDD/Fs in the samples, with 1,2,3,4,6,7,8-HpBDF the most abundant congener, found in half of the analysed pilot whales. The concentration range for ∑PBDD/Fs among the samples was 0.080-71 pg/g l.w. (lipid weight), and the sum of toxic equivalents ranged from 0.0039 to 4.7 pg TEQ/g l.w. No relationship was found between PBDD/Fs and PCDD/Fs. In addition, 20 pilot whale samples from the period 2010-2013 were analysed for PBDEs. Several PBDE congeners were found in all of the sampled pilot whales, and at noticeably higher levels than PBDD/Fs and PCDD/Fs. The ∑PBDEs ranged from 140 to 1900 ng/g l.w., with BDE #47 the most abundant congener detected in the samples. Results from the present study were then compared with data from previous studies on pilot wales to investigate temporal trends between 1986 and 2013. The comparison indicated that PBDE concentrations in juvenile males have decreased from 1996 to the latest observations in 2013. No relationship between the concentration levels of PBDD/Fs and PBDEs in the sampled pilot whales could be identified, which indicates possible differences in the metabolism of, or exposure to, PBDEs and PBDD/Fs.

Temporal trends of PBDD/Fs, PCDD/Fs, PBDEs and PCBs in ringed seals from the Baltic Sea (Pusa hispida botnica) between 1974 and 2015.

Temporal trends in exposure to persistent organic pollutants (POPs) were assessed in 22 pooled samples gathered from 69 individuals of Baltic ringed seal (Pusa hispida botnica) from 1974 to 2015. Samples were analysed for polybrominated dibenzo-p-dioxins and furans (PBDD/Fs), polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). No previous study has reported on the occurrence of PBDD/Fs in marine mammals in the Baltic Sea. Concentrations of pollutants in Baltic ringed seal, a marine mammal and top predator, can be used as an indicator of pollutants concentrations in the Baltic region. Visual inspection of data did not show any temporal trends for PBDD/Fs, while the PCDD/Fs and PCBs showed decreasing concentrations between 1974 and 2015. PBDEs increased until the end of the 1990s and then decreased until the end of the period. ∑PBDD/Fs ranged from 0.5-52.3pg/g lipid weight (l.w.) (0.08-4.8pgTEQ/g l.w.), with 1,2,3,4,6,7,8-HpBDF contributing on average 61% to ∑PBDD/Fs. ∑PCDD/Fs ranged from 103 to 1480pg/g l.w. (39-784pgTEQ/g l.w.), with 1,2,3,6,7,8-HxCDD, 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF showing the highest average concentrations. PBDD/F toxic equivalents (TEQ) contributed on average 1.1% to the total (PBDD/F+PCDD/F) TEQ. The ∑PBDEs concentration range was 18.7-503ng/g l.w., with BDE #47 the predominant congener. The concentration range for ∑PCBs was 2.8-40.1µg/g l.w., with #138 and #153 the most abundant congeners. Visual inspection of the data showed decreasing concentrations for all compound groups except PBDD/Fs. A slight increase in the PBDD/Fs concentrations was observed from 2004 onwards. This observation needs to be investigated further.

Uptake and bioaccumulation of PCDD/Fs in earthworms after in situ and in vitro exposure to soil from a contaminated sawmill site.

Uptake of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) was studied in earthworms collected from a sawmill site in Sweden with severe PCDD/Fs contamination (the hot spot concentration was 690,000ng TEQWHO2005/kg d.w.) in order to investigate the transfer of PCDD/Fs from the site to the biota. PCDD/Fs concentrations in the collected earthworms were compared to PCDD/Fs concentrations in laboratory exposed earthworms (Eisenia fetida), which were exposed to contaminated soils from the sawmill site for 34days. All analyses were performed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). PCDD/Fs concentrations in the earthworms ranged from 290 to 520,000pg/g (f.w.). The main congeners found in both soils and earthworms were OCDF, 1234678-HpCDF, OCDD and 1234678-HpCDD. The study showed that the PCDD/Fs in the soil were biovailable to the earthworms and the PCDD/Fs concentrations in the soils correlated with the concentrations in the earthworms. Earthworm samples from soil with lower concentration had higher bioaccumulation factors than samples from soils with high concentration of contamination. Thus, a less contaminated soil could yield higher concentrations in earthworms compared to a higher contaminated soil. Assuming that when assessing risks with PCDD/F contaminated soil, a combination of chemical analysis of soil PCDD/Fs concentrations and bioavailability should be employed for a more comprehensive risk assessment.

The effect of 7 years of intense exercise training on patients with coronary artery disease.

The purpose of this study was to evaluate the effects of long-term exercise training on maximal aerobic exercise capacity, evidence of myocardial ischemia and plasma lipid-lipoprotein concentrations in patients with coronary artery disease. Nine men with coronary artery disease, aged 57 +/- 2 years, who had completed 12 months of supervised intense exercise training were restudied after 6 additional years during which they continued to exercise. The first 12 months of training resulted in a 44% increase in maximal oxygen consumption (VO2max) from 25.0 +/- 1.3 to 35.9 +/- 1.5 ml X kg-1 X min-1 (p less than 0.001). The VO2max after 6 additional years (total 7 years) of intense training was 36.8 +/- 2.4 ml X kg-1 X min-1. Plasma high density lipoprotein (HDL)-cholesterol concentration increased from 38 +/- 3 to 45 +/- 4 mg X dl-1 at 12 months and rose further to 53 +/- 5 mg X dl-1 at 6 years of follow-up (p less than 0.05). The atherogenic index (total cholesterol/HDL-cholesterol ratio) decreased from 5.8 +/- 0.4 to 4.9 +/- 0.4 by 12 months (p less than 0.01) and to 4.1 +/- 0.4 after 6 additional years of training (p less than 0.05). Although the maximal heart rate-pressure product was 14% higher after 12 months of training, maximal ST segment depression was significantly less, 0.27 +/- 0.06 versus 0.19 +/- 0.04 mV (p less than 0.05); this improvement was maintained after 6 years of additional training. These data provide evidence that the beneficial effects of a program of intense exercise training can be maintained for long periods in some motivated patients with coronary artery disease who continue to exercise.

Improvement in glucose tolerance after 1 wk of exercise in patients with mild NIDDM.

We investigated the effects of 1 wk of intense exercise on glucose tolerance in 10 men with abnormal glucose tolerance [7 had mild non-insulin-dependent diabetes mellitus (NIDDM), and 3 had impaired glucose tolerance]. The 7 days of exercise did not result in significant changes in body weight or maximal oxygen uptake. Plasma glucose concentration at 120 min averaged 227 +/- 23 mg/dl in an oral glucose tolerance test (OGTT) before and 170 +/- 18 mg/dl after the 7 days of exercise (P less than .001). There was a 36% reduction in the area under the glucose tolerance curve. Plasma insulin concentration at 120 min of the OGTT averaged 172 +/- 27 microU/ml before and 106 +/- 13 microU/ml after 7 days of exercise (P less than .001); the area under the insulin curve was decreased by 32%. In contrast to the response to 7 days of exercise, one bout of exercise did not result in an improvement in glucose tolerance. These results provide evidence that regularly performed, vigorous exercise can be effective in decreasing insulin resistance and improving glucose tolerance within 7 days in some patients with mild NIDDM.

Insulin sensitivity in postmenopausal women: independent and combined associations with hormone replacement, cardiovascular fitness, and body composition.

OBJECTIVE: The effects of combined physical activity and hormone replacement therapy (HRT) on insulin sensitivity in postmenopausal (PM) women are unclear. The purpose of the study was to test the following hypotheses: 1) PM women who have undergone vigorous exercise training have greater insulin sensitivity than PM women who are physically active and PM women who are sedentary, and 2) PM women using HRT have greater insulin sensitivity than PM women not using HRT. We also sought to determine whether body composition or cardiovascular fitness was the stronger predictor of insulin sensitivity in these women. RESEARCH DESIGN AND METHODS: Three groups of PM women classified as sedentary (n = 18), physically active (n = 19), and athletic (n = 23) underwent an insulin-modified frequently sampled intravenous glucose tolerance test to determine the insulin sensitivity index (SI) and dual-energy X-ray absorptiometry to determine body composition. RESULTS: There was a significant association between both physical activity (P = 0.036) and HRT (P = 0.007) and fasting plasma insulin levels. The athletic PM women had the lowest plasma insulin levels and the highest SI. Across all physical activity levels, PM women using HRT (n = 29) had significantly lower fasting plasma insulin levels and a lower SI than PM women not using HRT (n = 31). HRT was significantly (P = 0.025) associated with intravenous glucose tolerance (KG); the women not using HRT had a higher K(G); than the PM women using HRT (0.83 +/- 0.08 vs. 0.60 +/- 0.05% per minute). Percent body fat (r = -0.37, P = 0.004) and VO2max (r = 0.35, P = 0.007) were similar predictors of SI. CONCLUSIONS: We conclude that, although overall HRT was associated with an attenuated SI, vigorous exercise training was independently associated with the greatest SI. In addition, PM women using HRT may benefit from having lower plasma insulin levels, but they may also have a lower SI.

Effect of exercise intensity on glucose and insulin metabolism in obese individuals and obese NIDDM patients.

OBJECTIVE: The primary purpose of this study was to evaluate the acute effect of exercise of differing intensity on plasma glucose and insulin responses to an oral glucose challenge. RESEARCH DESIGN AND METHODS: Six obese men and six obese men with NIDDM of similar age, weight, percentage body fat, and VO2peak participated in the study. Each subject underwent two 7-day exercise programs in a counterbalanced order at 2-week intervals. During each 7-day exercise period, the subjects cycled every day at a power output corresponding to 50% VO2peak for 70 min or 70% VO2peak for 50 min. Muscle glycogen utilization was estimated during exercise on day 7 using a [3H]glucose infusion technique in conjunction with indirect calorimetry. During the day before and after each 7-day exercise period, a 3-h oral glucose tolerance test (OGTT) was administered after a 12-h overnight fast. RESULTS: The average caloric expenditure did not differ between exercise at 50 and 70% VO2peak in both obese and obese NIDDM subjects. However, the carbohydrate oxidation was higher (P < 0.05) during exercise at 70 than 50% VO2peak in obese subjects (77 +/- 5 vs. 68 +/- 6 g) and obese NIDDM subjects (70 +/- 4 vs. 58 +/- 6 g). Muscle glycogen utilization was also higher (P < 0.05) during exercise at 70 than 50% VO2peak in obese subjects (59 +/- 9 vs. 30 +/- 7 g) and in obese NIDDM subjects (48 +/- 5 vs. 24 +/- 5 g). In obese subjects, plasma glucose response area during the OGTT did not change after 7 days of exercise at either 50 or 70% VO2peak. Plasma insulin response area during the OGTT also did not change after 7 days of exercise at 50% VO2peak. However, plasma insulin response area was reduced (P < 0.05) after 7 days of exercise at 70% VO2peak (9,644 +/- 1,783 vs 7,538 +/- 1,522 microU.ml-1.180 min-1). In obese NIDDM subjects, both plasma glucose and insulin response areas during the OGTT did not decrease after 7 days of exercise at either 50 or 70% VO2peak. CONCLUSIONS: It is concluded that the exercise-induced improvement in insulin sensitivity is influenced by exercise intensity in obese individuals. The improved insulin sensitivity after 7 days of exercise at 70% VO2peak in obese individuals may be related to greater muscle glycogen utilization during exercise. The lack of improvement in glucose tolerance and insulin sensitivity after 7 days of exercise at either 50 or 70% VO2peak in obese NIDDM patients may be due to the fact that the NIDDM patients selected in the present study were relatively hypoinsulinemic.

APO E gene and gene-environment effects on plasma lipoprotein-lipid levels.

Apolipoprotein E (apo E) is important in plasma lipid metabolism and is a component of several plasma lipoprotein-lipid particles. Three major apo E isoforms are encoded by three common alleles at the APO E locus. The E2 allele is associated with lower and the E4 allele with higher total plasma cholesterol and LDL cholesterol levels compared with the E3 allele. Available data generally indicate that APO E2, and possibly E3, genotype individuals reduce plasma total and low-density lipoprotein (LDL) cholesterol levels more than APO E4 individuals with statin therapy. Some evidence also indicates that APO E2 individuals are more likely to respond favorably to gemfibrozil and cholestyramine. On the other hand, it appears that with probucol, APO E4 genotype individuals may improve plasma lipoprotein-lipid profiles more than APO E3 individuals. APO E2 and E3 genotype perimenopausal women appear to improve plasma lipoprotein-lipid profiles more with hormone replacement therapy than APO E4 women. On the other hand, low-fat diet interventions tend to reduce plasma LDL cholesterol and, perhaps, plasma total cholesterol levels more in APO E4 than in APO E2 or E3 individuals. Both cross-sectional and longitudinal studies generally indicate that APO E2 and E3 individuals improve plasma lipoprotein-lipid profiles more with exercise training than APO E4 individuals. Although these data are hardly definitive, they lend strong support for the possibility that in the near future individuals will be directed to what might be their optimal therapy for improving plasma lipoprotein-lipid profiles and cardiovascular disease risk based partially on APO E genotype.

Altered hemodynamics during exercise in older essential hypertensive subjects.

This study was designed to compare the resting and exercise hemodynamics of older adults with moderate hypertension with those of age-matched normotensive controls. Thirty-one hypertensive (20 men, 11 women; mean age, 63.9 +/- 2.8 years) and 28 normotensive subjects (15 men, 13 women; mean age, 62.6 +/- 2.4 years) were studied. There were no differences between the groups in terms of body weight, body composition, and maximal O2 consumption (VO2). At rest, there were no differences in VO2, cardiac output, stroke volume, or heart rate between the two groups, although systolic (158 +/- 13 vs 121 +/- 12 mm Hg) and diastolic blood pressures (94 +/- 7 vs 79 +/- 8 mm Hg) were higher in the hypertensive subjects. The hypertensive subjects' elevated blood pressure at rest was the result of a higher total peripheral resistance. During exercise, the hypertensive subjects had a lower cardiac output and stroke volume, no difference in heart rate and VO2, higher systolic, diastolic, and mean blood pressures, and a higher total peripheral resistance compared with their normotensive peers. The results indicate that older hypertensive persons have an altered cardiovascular response to exercise as compared with age-matched normotensive subjects. The responses also indicate that older essential hypertensive persons do not undergo excessive myocardial demands during exercise of the intensity usually prescribed in rehabilitation programs.

Impaired insulin sensitivity and maximal responsiveness in older hypertensive men.

This study examines the relation between blood pressure and insulin resistance in obese, sedentary middle-aged and older men. Eleven hypertensive and 17 normotensive subjects of comparable age (58.6 +/- 1.0 years, mean +/- SEM), percent body fat (27.7 +/- 0.7%), and maximal aerobic capacity (30.2 +/- 0.9 mL.kg-1.min-1) participated in this study. Glucose disposal (M, milligrams per kilogram of fat-free mass per minute) determined during a three-dose hyperinsulinemic euglycemic clamp was lower in the hypertensive than normotensive subjects at the low (M at 120 pmol/m2.min: 2.3 +/- 0.2 versus 3.2 +/- 0.3, P = .06), intermediate (M at 600 pmol/m2.min: 8.0 +/- 0.6 versus 10.4 +/- 0.6, P = .02), and high (M at 3000 pmol/m2.min: 13.5 +/- 0.5 versus 15.5 +/- 0.7, P = .04) insulin infusion rates. The calculated insulin concentration necessary for a half-maximal effect (EC50) was greater in the hypertensive than normotensive subjects (1164 +/- 168 versus 864 +/- 66 pmol/L, P = .03). In this population of normotensive and hypertensive men, systolic, diastolic, and mean arterial blood pressures were related to glucose disposal at these insulin infusion rates (r = -.35 to -.46, P < .05) as well as the EC50 (r = .42 to .44, P < .05). Thus, hypertensive obese, sedentary older men have a reduction in both sensitivity and maximal responsiveness to insulin that is directly related to the severity of hypertension independent of obesity and physical fitness.