HDL cholesterol across a spectrum of physical activity from quadriplegia to marathon running

Reducing endocrine metabolic disease risk in adults with chronic spinal cord injury: strategic activities conducted by the Ontario-Quebec RIISC team

PURPOSE

The Rehabilitation Interventions for Individuals with a Spinal Cord Injury in the Community (RIISC) team aimed to develop and evaluate innovative rehabilitation interventions to identify endocrine metabolic disease (EMD) risk, intending to reduce the frequency and severity of EMD related morbidity and mortality among adults living with chronic spinal cord injury or disease (SCI/D).

MATERIALS AND METHODS

An interprovincial team from Ontario and Quebec reviewed available EMD literature and evidence syntheses and completed an inventory of health services, policies and practices in SCI/D care. The review outcomes were combined with expert opinion to create an EMD risk model to inform health service transformation.

RESULTS

EMD risk and mortality are highly prevalent among adults with chronic SCI/D. In stark contrast, few rehabilitation interventions target EMD outcomes. The modelled solution proposes: 1) abandoning single-disease paradigms and examining a holistic perspective of the individual's EMD risk, and 2) developing and disseminating practice-based research approaches in outpatient community settings.

CONCLUSIONS

RIISC model adoption could accelerate EMD care optimization, and ultimately inform the design of large-scale longitudinal pragmatic trials likely to improve health outcomes. Linking the RIISC team activities to economic evaluations and policy deliverables will strengthen the relevance and impact among policymakers, health care providers and patients.

Acute Spinal Cord Injury Is Associated With Prevalent Cardiometabolic Risk Factors

OBJECTIVES

To (1) describe the prevalence of cardiometabolic disease (CMD) at spinal cord injury (SCI) rehabilitation discharge; (2) compare this with controls without SCI; and (3) identify factors associated with increased CMD.

DESIGN

Multicenter, prospective observational study.

SETTING

Five National Institute on Disability, Independent Living, and Rehabilitation Research Model SCI Rehabilitation Centers.

PARTICIPANTS

SCI (n=95): patients aged 18-70 years, with SCI (neurologic levels of injury C2-L2, American Spinal Injury Association Impairment Scale grades A-D), and enrolled within 2 months of initial rehabilitation discharge. Control group (n=1609): age/sex/body mass index-matched entries in the National Health and Nutrition Examination Education Survey (2016-2019) (N=1704).

INTERVENTIONS

None MAIN OUTCOME MEASURES: Percentage of participants with SCI with CMD diagnosis, prevalence of CMD determinants within 2 months of rehabilitation discharge, and other significant early risk associations were analyzed using age, sex, body mass index, insulin resistance (IR) by fasting glucose and Homeostasis Model Assessment (v.2), fasting triglycerides, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol, total cholesterol, and resting blood pressure (systolic and diastolic).

RESULTS

Participants with SCI had significantly higher diastolic blood pressure and triglycerides than those without SCI, with lower fasting glucose and HDL-C. A total of 74.0% of participants with SCI vs 38.5% of those without SCI were obese when applying population-specific criteria (P<.05). Low HDL-C was measured in 54.2% of participants with SCI vs 15.4% of those without (P<.05). IR was not significantly different between groups. A total of 31.6% of participants with SCI had ≥3 CMD determinants, which was 40.7% higher than those without SCI (P<.05). Interplay of lipids and lipoproteins (ie, total cholesterol:HDL-C ratio and triglyceride:HDL-C ratio) were associated with elevated risk in participants with SCI for myocardial infarction and stroke. The only significant variable associated with CMD was age (P<.05).

CONCLUSIONS

Individuals with SCI have an increased CMD risk compared with the general population; obesity, IR, and low HDL-C are the most common CMD risk determinants; age is significantly associated with early CMD.

Guideline Approaches for Cardioendocrine Disease Surveillance and Treatment Following Spinal Cord Injury

PURPOSE OF REVIEW

Persons with spinal cord injuries (SCI) commonly experience individual risks and coalesced health hazards of the cardiometabolic syndrome (CMS). This review will examinethe role of exercise and nutritional intervention as countermeasures to these disease risks.

RECENT FINDINGS

The CMS hazards of overweight/obesity, insulin resistance, hypertension, and dyslipidemia are strongly associated with physical deconditioning and are common after SCI. Both the CMS diagnosis and physical deconditioning worsen the prognosis for all-cause cardiovascular disease occurring early after SCI. Evidence supports a therapeutic role for physical activity after SCI as an effective countermeasure to these risks and often represents the first-line approach to CMS abatement. This evidence is supported by authoritative systematic reviews and associated guidelines that recommend specific activities, frequencies, and activities of work. In many cases, the most effective exercise programming uses more intense periods of work with limited rest. As SCI is also associated with poor dietary habits, including excessive energy intake and saturated fat consumption, more comprehensive lifestyle management incorporating both exercise and nutrition represents a preferred approach for overall health management.

SUMMARY

Irrespective of the interventional strategy, improved surveillance of the population for CMS risks and encouraged incorporation of exercise and nutritional management according to recent population-specific guidelines will most likely play an important role in the preservation of activity, optimal health, and independence throughout the lifespan.

Nutritional Health Considerations for Persons with Spinal Cord Injury

Chronic spinal cord injury (SCI) often results in morbidity and mortality due to all-cause cardiovascular disease (CVD) and comorbid endocrine disorders. Several component risk factors for CVD, described as the cardiometabolic syndrome (CMS), are prevalent in SCI, with the individual risks of obesity and insulin resistance known to advance the disease prognosis to a greater extent than other established risks. Notably, adiposity and insulin resistance are attributed in large part to a commonly observed maladaptive dietary/nutritional profile. Although there are no evidence-based nutritional guidelines to address the CMS risk in SCI, contemporary treatment strategies advocate more comprehensive lifestyle management that includes sustained nutritional guidance as a necessary component for overall health management. This monograph describes factors in SCI that contribute to CMS risks, the current nutritional profile and its contribution to CMS risks, and effective treatment strategies including the adaptability of the Diabetes Prevention Program (DPP) to SCI. Establishing appropriate nutritional guidelines and recommendations will play an important role in addressing the CMS risks in SCI and preserving optimal long-term health.

Effect of training intensity on physical capacity, lipid profile and insulin sensitivity in early rehabilitation of spinal cord injured individuals

STUDY DESIGN

Pre-post training intervention.

OBJECTIVES

To evaluate the effect of training intensity on physical capacity, lipid profile and insulin sensitivity in early rehabilitation of spinal cord injured (SCI) patients, and to assess the correlation between peak aerobic capacity (VO(2Peak)) and insulin sensitivity.

SETTING

Spinal Cord Rehabilitation Unit, Sunnaas Hospital, Nesoddtangen, Norway.

METHOD

Six recently injured SCI individuals participated in the arm training intervention and were randomly admitted to a high-intensity (HI; 70-80% heart rate reserve (HRR)) and low-intensity (LI; 40-50% HRR) group. The 1 h interval training consisted of 3 min exercise bouts interspersed with 2 min of rest, three times a week for 8 weeks. In addition, a correlation coefficient was obtained between VO(2Peak) and insulin sensitivity in 11 SCI patients.

RESULTS

The 8-week training program resulted in a significant increase in VO(2Peak) and maximal power output (PO(Max)) for the group as a whole (P<0.05). VO(2Peak) increased significantly more and total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) ratio and triglycerids decreased significantly more in the HI group than in the LI group (P=0.05). Training-induced changes in insulin sensitivity were significantly different between the groups (P=0.05), which was due to a nonsignificant decline in insulin sensitivity in the HI group and a nonsignificant improvement in the LI group. A significant positive correlation was found between VO(2peak) and insulin sensitivity (r=0.68, P=0.02).

CONCLUSION

The interval arm training protocol as used in the present study enables recently injured SCI patients to do substantial work at a relatively high intensity. Results indicate that improvements in physical capacity and lipid profile were more pronounced in response to high-intensity training. The significant correlation between maximal oxygen consumption and insulin sensitivity indicates that, as in the able-bodied population, peak aerobic capacity is a predictive value with regard to insulin sensitivity in SCI. Future studies with larger groups assessing the role of exercise intensity on insulin sensitivity in SCI are suggested.

31st g. Heiner sell lectureship: secondary medical consequences of spinal cord injury

Persons with spinal cord injury (SCI) have secondary medical consequences of paralysis and/or the consequences of extreme inactivity. The metabolic changes that result from reduced activity include insulin resistance with carbohydrate disorders and dyslipidemia. A higher prevalence of coronary artery calcification was found in persons with SCI than that in matched able-bodied controls. A depression in anabolic hormones, circulating testosterone and growth hormone, has been described. Adverse soft tissue body composition changes of increased adiposity and reduced skeletal muscle are appreciated. Immobilization is the cause for sublesional disuse osteoporosis with an associated increased risk of fragility fracture. Bowel dysmotility affects all segments of the gastrointestinal tract, with an interest in better defining and addressing gastroesophageal reflux disease and difficulty with evacuation. Developing and testing more effective approaches to cleanse the bowel for elective colonoscopy are being evaluated. The extent of respiratory dysfunction depends on the level and completeness of SCI. Individuals with higher spinal lesions have both restrictive and obstructive airway disease. Pharmacological approaches and expiratory muscle training are being studied as interventions to improve pulmonary function and cough strength with the objective of reducing pulmonary complications. Persons with spinal lesions above the 6th thoracic level lack both cardiac and peripheral vascular mechanisms to maintain blood pressure, and they are frequently hypotensive, with even worse hypotension with upright posture. Persistent and/or orthostatic hypotension may predispose those with SCI to cognitive impairments. The safety and efficacy of anti-hypotensive agents to normalize blood pressure in persons with higher level cord lesions is being investigated.

Non-conventional hemostatic risk factors for coronary heart disease in individuals with spinal cord injury

STUDY DESIGN

Review.

OBJECTIVES

In subjects with spinal cord injury (SCI), there is strong evidence for platelet hyperactivity, which may stimulate atherosclerosis and coronary heart disease (CHD). The literature was reviewed.

BACKGROUND

Individuals with SCI develop premature CHD. In addition to the conventional risk factors associated with CHD, there are pathologic hematological factors involved in atherogenesis that are similar to those that have been demonstrated in individuals with diabetes, and these hematological factors might affect individuals with SCI. One such hematological factor, platelet aggregation, is essential for the development of CHD, which results from thrombus formation in the coronary vasculature. Prostacyclin (PGI(2)) is a potent inhibitor of platelet aggregation and is thought to have a beneficial role in inhibiting atherogenesis; therefore, it is possible that individuals with SCI have impaired PGI(2) receptor function.

METHODS

We reviewed the literature by conducting a search using PubMed (1970-2007).

RESULTS

Acute thrombosis is emerging as an important factor in the etiology of CHD and therefore could mediate the risk of CHD in persons with SCI, in addition to previously known risk factors such as hyperlipidemia, hypertension, hyperlipidemia, diabetes mellitus and hyperinsulinemia. Because PGI(2) may retard atherogenesis through its inhibitory effects on platelet function, we discuss the effects of PGI(2) on platelets in persons with SCI in this review.

CONCLUSIONS

Subjects with chronic SCI develop abnormal platelet function, resulting in the production of atherogenic and thrombogenic factors for the following reasons: (1) the PGI(2) and insulin receptors on their platelets are impaired; (2) thrombin generation and platelet-derived growth factor release are elevated; (3) insulin-induced nitric oxide production by platelets is markedly impaired; and (4) a circulating antibody (immunoglobulin G (IgG)) blocks the antithrombotic effect of both insulin and PGI(2) receptors. Thus, this IgG molecule is thought to be one of the pathological mediators of the increased incidence of CHD in individuals with SCI.

Safety, tolerance, and efficacy of extended-release niacin monotherapy for treating dyslipidemia risks in persons with chronic tetraplegia: a randomized multicenter controlled trial

OBJECTIVE

To test the safety, tolerance, and efficacy of extended-release niacin monotherapy on dyslipidemia in persons with chronic tetraplegia.

DESIGN

Placebo-controlled, blinded, multicenter, randomized controlled trial.

SETTING

Three spinal cord injury research/rehabilitation centers.

PARTICIPANTS

Persons with chronic tetraplegia (N=54) and low plasma high-density lipoprotein cholesterol (HDL-C) levels.

INTERVENTION

Extended-release niacin monotherapy (48 weeks; n=31) on a dose-titration schedule versus matched placebo (n=23).

MAIN OUTCOME MEASURES

Safety was assessed by using percentages of treatment-emergent adverse events and increased levels of hepatic transaminases, uric acid, glycosylated hemoglobin, and fasting glucose. Tolerance was assessed by using participant reports for frequency and intensity of adverse effects of extended-release niacin. Primary effectiveness outcomes were fasting HDL-C level and plasma total cholesterol (TC)/HDL-C ratio. Secondary outcomes included plasma low-density lipoprotein cholesterol (LDL-C) and TC levels and LDL-C/HDL-C ratio.

RESULTS

Significant increases in fasting HDL-C levels (24.5%) were accompanied by decreases in TC/HDL-C and LDL-C/HDL-C ratios, LDL-C levels, and TC levels (all P<.05). No evidence of sustained hepatotoxicity or hyperglycemia was observed. Treatment-emergent withdrawals (12.9%) accompanied flushing (n=1), hypotension/presyncope (n=1), and diarrhea (n=2). One subject experienced transient hyperuricemia. Other drug-reported symptoms did not differ from those for placebo.

CONCLUSIONS

Extended-release niacin monotherapy is safe, tolerated, and effective for most persons with chronic tetraplegia. Special precautions for changes in bowel habits and postadministration hypotension should be observed.

The potential metabolic consequences of cerebral palsy: inferences from the general population and persons with spinal cord injury

The metabolic consequences of cerebral palsy (CP) have not been reported. The observations and suggestions presented in this article are based on our current knowledge of physiology in the general population and on information on the known metabolic consequences of disability in persons with spinal cord injury. Because of pain, fatigue, and other secondary consequences of CP, adolescents with CP who are ambulatory may become less physically active with age. This phenomenon would be expected to be associated with deconditioning and adverse changes in body composition including atrophy of muscles and an absolute or relative increase in adiposity. Insulin resistance, hyperinsulinemia, and associated adverse metabolic changes may develop. In an unfavorable metabolic milieu, the ability of the pancreas to compensate for mild elevations of circulating glucose may diminish. The combination of reduced fitness and conventional risk factors for cardiovascular disease would be expected to increase the risk for coronary heart disease (CHD); however, there has been no assessment of the risk factors for CHD in adults with CP. Once subgroups with modifiable risk factors for cardiovascular disease have been identified, risk factors for CHD should be aggressively treated, according to current standards of care.

The influence of exercise training on plasma lipids and lipoproteins in health and disease

There is a very high probability that lipoprotein metabolism plays a central role in the etiology of coronary heart disease. In sedentary persons one way to favorably alter lipoprotein metabolism and possibly delay the progression of coronary atherosclerosis is by an increase in their habitual physical activity. More physically active persons tend to have lower plasma triglycerides and very low density lipoprotein concentrations, and a greater high-density lipoprotein mass due to higher concentrations of the subfraction HDL2 and apoprotein A-I. Plasma low-density lipoprotein concentrations usually are not significantly reduced by exercise unless accompanied by weight loss, but there may be important changes in the distribution among the low-density subfractions. These exercise effects are most likely mediated by alterations in the activity of enzymes involved in the synthesis, transport and catabolism of the various lipoproteins including lipoprotein lipase, hepatic lipase and lecithin: cholesterol acyltransferase. In healthy persons as well as in patients with ischemic heart disease, diabetes and renal failure, an increase in moderate-intensity, endurance-type activity requiring an expenditure of approximately 4 MJ (1,000 kcal) per week usually produce favorable lipoprotein changes. Above this level a dose-response relationship exists, with greater changes occurring up to energy expenditures of 19 MJ (4,500 kcal) per week.

Objective measures of neighborhood environment and self-reported physical activity in spinal cord injured men

OBJECTIVES

To assess the relationship between objective neighborhood environment and self-reported physical activity (PA) and between PA and obesity-related risk factors in people with spinal cord injury (SCI).

DESIGN

A cross-sectional study.

SETTING

Urban university.

PARTICIPANTS

Men with SCI (N=131), 20 to 59 years old, at least 1 year postinjury and using wheelchair for mobility most of the time.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Metabolic syndrome (abdominal obesity, elevated blood pressure, glucose, triglycerides, and low-high density lipoprotein cholesterol) and high C-reactive protein (CRP), as well as total PA metabolic equivalent score.

RESULTS

Lower PA was associated with higher prevalence rate for elevated triglycerides, metabolic syndrome, and high CRP. Compared with those in low PA tertile, those in high PA tertile had significantly lower odds for elevated triglycerides (odds ratio [OR]=.19; 95% confidence interval [CI], .04-.80), metabolic syndrome (OR=.15; 95% CI, .03-.66) and high CRP (OR=.17; 95% CI, .04-.71) while adjusting for relevant factors. In crude analysis, lower PA was associated with neighborhood environmental characteristics including shorter distance to nearest transit stops, smaller mean block area, greater number of transit stops, high vacant housing, and higher neighborhood crime rate. In multivariate analysis higher total crime was the only risk factor significantly associated with lower PA level. Those living in higher crime rate neighborhoods had 86% lower odds of having greater than median PA level (OR=.14; 95% CI, .04-.49) than their counterparts.

CONCLUSIONS

In men with SCI, lower PA is independently associated with having elevated triglycerides, metabolic syndrome, and high CRP. Additionally, lower PA is associated with higher neighborhood crime rate.

Coronary heart disease in individuals with spinal cord injury: assessment of risk factors

STUDY DESIGN

Discussion document.

OBJECTIVES/METHOD

To review the work performed on conditions and disorders that predispose persons with spinal cord injury (SCI) to an increased risk of coronary heart disease (CHD).

RESULTS/DISCUSSION

Individuals with SCI have an increased prevalence of abnormalities in carbohydrate and lipid metabolism because of immobilization, muscle atrophy and relative adiposity. In those with SCI, an inverse relationship has been reported between serum high-density lipoprotein (HDL) cholesterol values and abdominal circumference, and a direct relationship between serum triglycerides levels and abdominal circumference. Persons with SCI have lower serum HDL cholesterol levels than able-bodied controls. A higher prevalence of insulin resistance and diabetes mellitus, as well as an earlier occurrence of coronary heart disease (CHD), has been reported in persons with SCI than in the general population. Recently, a higher prevalence and greater degree of coronary artery calcification by electron beam computerized tomography has been demonstrated in persons with SCI, even if matched with the able-bodied population for age, gender, ethnicity and conventional risk factors for CHD. Knowledge of relative risk of CHD in persons with SCI is important for appropriate intervention strategies. The conventional risk factors for CHD were determined in veterans with SCI to assign risk to determine target low-density lipoprotein cholesterol levels for therapeutic intervention. Limitations of conventional guidelines when applied to the SCI population should be appreciated. Conventional risk factors for CHD should be identified and treated in individuals with SCI, according to current standards of care.

Different risk factor patterns for metabolic syndrome in men with spinal cord injury compared with able-bodied men despite similar prevalence rates

OBJECTIVE

To determine if the prevalence of metabolic syndrome and risk factors differs between age- and race-matched men with spinal cord injury (SCI) and able-bodied men.

DESIGN

Cross-sectional.

SETTING

Urban university.

PARTICIPANTS

Men with SCI (n=185), ages 20 to 59 years, were matched 1 to 1 with able-bodied men from the 1999-2002 National Health and Nutrition Examination Surveys.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Waist circumference, blood pressure, glucose, triglyceride (TG), total (TC), and low- (LDL) and high-density lipoprotein (HDL) cholesterol.

RESULTS

Despite similar prevalence for metabolic syndrome, different risk factor patterns were found between groups. Men with SCI had a significantly lower mean HDL, TG, and glucose in addition to lower TC and LDL. After adjusting for smoking, education, and household income by using conditional logistic regression, men with SCI had a higher risk for abdominal obesity (odd ratio [OR]=1.78; 95% confidence interval [CI], 1.07-2.96) and reduced HDL (OR=1.76; 95% CI, 1.06-2.94) but lower risks for elevated glucose (OR=0.55; 95% CI, 0.33-0.94) than their able-bodied counterparts. By using linear regression and controlling for waist circumference, men with SCI had lower TC, LDL, TG, and glucose concentrations but lower HDL. Racial differences in risks were found in both SCI and able-bodied men; however, among the SCI men, prevalence for low HDL and elevated glucose was similar between whites and African Americans.

CONCLUSIONS

Men with SCI do not appear to have an increased prevalence of metabolic syndrome compared with able-bodied counterparts, suggesting that other nontraditional risks may contribute to their increased mortality from cardiovascular disease and diabetes.

Acute peripheral blood flow response induced by passive leg cycle exercise in people with spinal cord injury

OBJECTIVE

To determine the acute femoral artery hemodynamic response in paraplegic subjects during a passive leg cycle exercise.

DESIGN

Case series.

SETTING

Department of physical medicine and rehabilitation in a university in France.

PARTICIPANTS

A volunteer sample of 15 people with traumatic spinal cord injury.

INTERVENTION

Subjects performed a 10-minute session of passive leg cycle exercise in the sitting position.

MAIN OUTCOME MEASURES

We measured heart rate, maximal (Vmax), and minimal femoral artery blood flow velocity at rest and immediately after the passive leg cycle exercise, using quantitative duplex Doppler ultrasound. We calculated mean blood flow velocity (Vmean) and velocity index, representing the peripheral resistance, for each condition.

RESULTS

Vmax and Vmean increased (from .80+/-.18 m/s to .96+/-.24 m/s, P<.01; and from .058+/-.02 m/s to .076+/-.03 m/s, P<.01; respectively) after 10 minutes of passive leg cycle exercise. Heart rate did not change. The velocity index decreased from 1.23+/-0.15 to 1.16+/-0.21 (P=.038).

CONCLUSIONS

The results of this study suggest that acute passive leg cycle exercise increases vascular blood flow velocity in paralyzed legs of people with paraplegia. This exercise could have clinical implications for immobilized persons.

Body mass index and body composition measures by dual x-ray absorptiometry in patients aged 10 to 21 years with spinal cord injury

BACKGROUND/OBJECTIVE

To determine the body composition of adolescents with spinal cord injury (SCI) and to assess whether established cutoff values for obesity determined by body mass index (BMI) are valid for this population.

METHODS

Sixty patients, aged 10-21 years, with traumatic SCI (50 with paraplegia and 10 with tetraplegia) were compared with 60 gender-, age-, and BMI-matched controls (CTRL). Dual-energy x-ray absorptiometry was used to estimate regional and total bone mineral content, lean tissue mass, fat tissue mass, and body fat percentage. BMI was calculated from measured weight and stature (kg/m2).

RESULTS

Total percent body fat was significantly higher in the paraplegia group (31.4% +/- 1.2%; mean +/- SE) than in the tetraplegia and CTRL groups (25.7% +/- 2.7% and 22.9% +/- 1.1%, respectively). This change in percent total body fat was associated with a reduction of lean tissue mass in the paraplegia (37.6 +/- 1.1 kg; mean +/- SE) and tetraplegia (32.8 +/- 2.5 kg) subjects as compared to the CTRL group (46.2 +/- 1.0 kg; P < 0.001). Total fat mass was significantly greater in the paraplegia group (19.3 +/- 1.3 kg) than the CTRL and tetraplegia groups (14.9 +/- 1.2 kg and 11.7 +/- 3.0 kg, respectively). Regional measurements revealed that the greatest reduction of lean tissue mass in the SCI subjects occurred in the lower extremities, followed by the trunk. As a result of these changes in body composition, the optimal BMI for classifying obesity (trunk fat percent >30 in males and >35 in females) in subjects with SCI was 19 kg/m2 as compared to 25 kg/m2 in able-bodied subjects.

CONCLUSIONS

Patients aged 10 to 21 years with SCI have significantly decreased lean tissue mass and bone mineral content, and increased fat mass. As a result, traditional BMI cutoff criteria significantly underestimate obesity in this population. New clinically applicable criteria to define obesity should be established for SCI children and adolescents with SCI.

Evaluating the Prevalence of Silent Coronary Artery Disease in Asymptomatic Patients With Spinal Cord Injury

To evaluate the prevalence of coronary artery disease (CAD) in patients with spinal cord injury (SCI), 47 clinically asymptomatic SCI patients received thallium-201 myocardial perfusion single photon emission computed tomography (Tl-201 SPECT) after dipyridamole administration for the diagnosis of CAD. There were 4 groups as follows; group 1: 13 patients with quadriplegia and complete SCI, group 2: 11 patients with quadriplegia and incomplete SCI, group 3: 11 patients with paraplegia and complete SCI, and group 4: 12 patients with paraplegia and incomplete SCI. There were no significant differences in sex distribution, ages, SCI duration, or CAD risk factors among the SCI patients in the 4 groups. All Tl-201 SPECT images were interpreted by the agreement of 2 experienced nuclear medicine physicians without prior knowledge of the patients' histories. A total of 30 of 47 (63.8%) SCI patients had abnormal Tl-201 SPECT findings. Among the 4 groups of SCI patients, those in groups 1 and 4 had the significantly highest and lowest prevalences of abnormal Tl-201 SPECT findings, respectively. We concluded that combined quadriplegia and complete SCI is an important CAD risk factor in SCI patients based on the objective evidence of intravenous dipyridamole cardiac stress testing with Tl-201 SPECT.

Fitness, inflammation, and the metabolic syndrome in men with paraplegia

OBJECTIVE

To determine the relations among peak aerobic capacity, physical activity, functional ability, components of the metabolic syndrome (high-density lipoprotein cholesterol [HDL-C], triglycerides [TG], glucose, insulin, abdominal obesity, high blood pressure), and inflammatory factors (interleukin-6 [IL-6], C-reactive protein [CRP]) in men with paraplegia.

DESIGN

Cross-sectional exploratory design.

SETTING

University research laboratory.

PARTICIPANTS

Twenty-two men (age, 39+/-9y; duration of injury, 17+/-9y; level of injury, T2-L2) with functionally complete paraplegia volunteered to participate.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Peak aerobic capacity was measured using a graded peak exercise test with an arm ergometer, and physical activity was assessed by the Physical Activity and Disability Scale. Functional ability was assessed by the Self-Report Functional Measure. Circulating glucose, insulin, HDL-C, TG, total cholesterol, IL-6, and CRP levels were determined by specific enzyme or immunologic assays. Body fat was determined by dual-energy x-ray absorptiometry, and central obesity was estimated from abdominal sagittal diameters.

RESULTS

Lower peak aerobic capacities were associated with lower HDL-C and lower physical activity levels ( P <.014). Lower physical activity levels were associated with higher fasting glucose, lower HDL-C level, and larger abdominal sagittal diameters ( P <.036). Larger abdominal sagittal diameters were associated with higher fasting glucose, higher fasting and postload insulin, lower HDL-C, higher TG, and higher CRP levels ( P <.05).

CONCLUSIONS

Diet and exercise trials are needed to determine the efficacy and effectiveness of lifestyle interventions aimed at slowing the progression of the metabolic syndrome in people with spinal cord injury.

Effects of long-term negative energy balance with exercise on plasma lipid and lipoprotein levels in identical twins

Plasma lipid and lipoprotein concentrations were measured before and after a 58,000kcal (244MJ) negative energy balance protocol induced entirely by supervised endurance exercise over a 93-day period in seven pairs of young sedentary and healthy male monozygotic twins. The negative energy balance induced significant changes in all measures of body weight and composition except fat free mass. The mean weight loss was 5.0+/-0.6kg, and it was entirely accounted for by the loss of body fat. In response to the program, improvement in the plasma lipid profile was seen including decreases in plasma total (P=0.028) and low density lipoprotein (LDL) (P=0.004) cholesterol; total cholesterol/high density lipoprotein (HDL) cholesterol ratio (P=0.002); and HDL apolipoprotein A-I concentration (P=0.062). Statistically significant within-pair resemblance was found for the changes in total and very low density lipoprotein (VLDL) cholesterol; total, VLDL and LDL triglycerides, and total, VLDL and LDL apolipoprotein B. The findings suggest that favorable changes in the lipid profile can be obtained through chronic negative energy balance achieved by clamping daily energy intake and adding daily moderate intensity exercise even in persons with relatively normal lipid levels at baseline. Furthermore, within-pair resemblance among twin brothers strongly suggests that genetic differences partially account for the variation in the response of lipids and lipoproteins to the negative energy balance protocol.

The implementation of a fitness program for children with disabilities: a clinical case report

PURPOSE

The purpose of this report is to describe a community-based fitness program developed and implemented for children with disabilities. Several outcomes are reported for one of the participants, J, an 11-year-old girl with hypotonia and mild mental retardation, to illustrate the strengths and limitations of this program and to help guide clinicians and researchers in developing and critically assessing the effectiveness of similar programs.

SUMMARY OF KEY POINTS

The fitness program, called "Off the Couch," (OTC) was provided in six-week sessions for one hour per week. Outcomes examined included the energy expenditure index (EEI), rating of perceived exertion (RPE), maximum running velocity, and the overall daily activity level of the child and the number of exercise sessions that the child participated in over a two-week time period. J demonstrated a reduction in EEI and a slight improvement in maximum running velocity. Activity level remained at a relatively high level. The program is discussed with respect to feasibility in a clinical setting, suggestions for similar programs and areas for related research. J's outcomes are discussed in terms of their functional relevance.

Factors influencing body composition in persons with spinal cord injury: a cross-sectional study

To determine the body composition differences across age, 133 men with chronic spinal cord injury (SCI) (66 with tetraplegia, 67 with paraplegia) were compared with an age-, height-, and ethnicity-matched able-bodied male reference population (n = 100) using two different dual-energy X-ray absorptiometry densitometers. The effects of duration of injury, level, and completeness of lesion were analyzed in the SCI population. Independent of age, total body and regional lean mass were lower and fat mass was higher in persons with SCI compared with controls. The SCI group was 13 +/- 1% (means +/- SE) fatter per unit of body mass index (kg/m2) compared with the control group (P < 0.0001). Advancing age was strongly associated with less lean mass and greater adiposity in those with SCI, whereas it was mildly related in the controls. Total body and regional arm and trunk, but not leg, lean tissues were lower in subjects with SCI, across all ages, than in the controls. In summary, persons with SCI were fatter for any body mass index and demonstrated significantly less lean and more adipose tissues for any given age compared with controls.

Blood lipid response to 20 weeks of supervised exercise in a large biracial population: the HERITAGE Family Study

We studied the effects of 20 weeks of supervised cycle-ergometer exercise on plasma lipids in 675 healthy, sedentary, normolipidemic white and black men and women aged 17 to 65 years, participating in the HERITAGE Family Study. Fasting plasma lipids were assessed twice at baseline and 24 and 72 hours after the last exercise session and adjusted for plasma volume changes. No significant differences from the mean baseline levels were observed for total, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) cholesterol and apolipoprotein B (Apo B). A significant reduction (P < .01) from baseline levels in plasma total and VLDL triglycerides was observed only in the 24-hour posttraining specimens, reflecting a response to the last bout of exercise. High-density lipoprotein (HDL) cholesterol increased 3.6% for the combined group, primarily due to an increase in HDL2, with an associated increase in Apo A-1 (P < .001). No significant differences were noted in the HDL response by sex, race, or age. An inverse correlation (r = -.241) was observed between the increase in HDL cholesterol and change in body fat only in men, and the increase in HDL cholesterol was unrelated to the change in maximal oxygen uptake (VO2max).

Physical activity and high density lipoprotein cholesterol levels: what is the relationship?

High density lipoprotein cholesterol (HDL-C) levels are strongly, inversely and independently associated with coronary heart disease (CHD). Increased physical activity is associated with reduced CHD mortality. This protection against CHD may partially be explained by the increase in HDL-C levels observed following aerobic exercise training. Many also agree that an exercise threshold needs to be met before such favourable changes in HDL-C metabolism can occur. Most likely, the exercise-induced changes in HDL-C are the result of the interaction amongst exercise intensity, frequency, duration of each exercise session and length of the exercise training period. Although a relative contribution of each exercise component (intensity, duration and frequency) is also likely, it has not been established. There is also substantial support for a dose-response relationship. Favourable changes in HDL-C appear to occur incrementally and reach statistical significance at approximately 7-10 miles per week or 1200 to 1600kcal. Exercise-induced changes in HDL-C may also be gender dependent. The volume of exercise required to increase HDL-C levels appears to be substantially more for women than men. This perhaps is due to higher HDL-C levels in women at baseline compared with men. However, the many other health benefits derived from increased physical activity should encourage women to participate in regular exercise regardless of the exercise effects on HDL-C levels. A practical approach in prescribing exercise for patients is to use moderate intensity exercises (70 to 80% of predicted maximal heart rate), 3 to 5 times per week, for a total of 7 to 14 miles per week. This is equivalent to approximately 1200 to 1600kcal per week. Moderate to low intensity exercise should be preferred because such exercise carries a lower risk for cardiac complications. In addition, patients are more likely to participate and sustain a lower than higher intensity exercise programme. It is also important to recognise that other modes of physical activity can also be encouraged for patients. Such activities should be associated with similar increases in HDL-C levels as long as they meet or exceed the caloric expenditure of 1200 to 1600kcal (7 to 14 miles per week of jogging).

Serum lipids during the first year following acute spinal cord injury

Patients with chronic spinal cord injury (SCI) have low levels of high-density lipoprotein (HDL) cholesterol. The cause of this abnormality and its relation to SCI are unknown. We studied 100 consecutively admitted males with acute SCI prospectively for 1 year to determine changes in serum lipids following acute SCI and the relation of these changes to the level of injury and physical activity. Low-density lipoprotein (LDL), HDL, and total cholesterol and triglycerides were all decreased following acute SCI and gradually increased toward normal by 1 year. Serum HDL, LDL, and total cholesterol levels correlated with the level of SCI: levels were lower in quadriplegic compared with paraplegic patients. Serum HDL showed the greatest change following SCI, increasing by 26% in quadriplegic and 18% in paraplegic patients. These changes in serum lipid levels could not be explained by changes in alcohol consumption or body weight. We estimated that only 44% of the increase in HDL following SCI was associated with an increase in physical activity. We postulate that interruption of the autonomic nervous system influences lipid metabolism and serum lipid levels.

Measurement of body fat in individuals with tetraplegia: a comparison of eight clinical methods

Spinal cord injury (SCI) is a unique condition that markedly alters body composition, raising the possibility of having undefined effects on the traditional assumptions for body composition. In order to determine appropriate methods for the analysis of body composition in this population, 12 subjects with tetraplegia were studied for absolute weight as fat and percent fat by the following methods; bioelectrical impedance (BIA), dual energy X-ray absorptiometry (DEXA), total body potassium (TBK), total body water (TBW), and four anthropometric methods: Durnin and Womersley (DUR), Jackson and Pollack (J and P), Sloan (SLN) and Steinkamp et al (STK). The eight methods were compared with the mean of all means (24.4 +/- 2.2% fat), which was assumed to be the best estimate of percent fat. Four methods: BIA, DEXA, TBW and STK were not significantly different, while TBK, DUR, J&P and SLN were significantly (P < 0.009) different from the mean of the means. Using only the non-significantly different methods, repeat computation revealed TBW to have the smallest difference from the mean (0.1 +/- 2.8%), and DEXA to have the strongest correlation with the line of identity (r = 0.96, P < 0.0001). In conclusion, BIA, DEXA, TBW, and STK are equally valuable for estimating fat in those with tetraplegia.

Tomographic thallium-201 myocardial perfusion imaging after intravenous dipyridamole in asymptomatic subjects with quadriplegia

Cardiovascular disease is the leading cause of mortality in those with a spinal cord injury (SCI). As a consequence of changes in body composition and level of activity, individuals with a SCI tend to have a high prevalence of multiple risk factors for coronary artery disease (CAD). In this report, we have demonstrated the usefulness of tomographic thallium-201 myocardial perfusion imaging after intravenous dipyridamole in six clinically asymptomatic subjects with quadriplegia. The average age of the subjects was 47 +/- 2 years, and they had a duration of injury of 15 +/- 2 years. On average, the individuals had five risk factors for CAD. After intravenous administration of dipyridamole and mild upper extremity exercise, the subjects reported no adverse symptoms and had no electrocardiographic evidence suggestive of ischemia. By contrast, three of the six subjects had reversible defects noted on thallium scintigraphy, and one additional subject had a fixed defect that was suggestive of infarction. The remaining two subjects had abnormal scans with fixed defects of the inferioposterior region, which may be ascribed to diaphragmatic attenuation, perhaps a result of partial diaphragmatic paralysis. Thus, dipyridamole thallium myocardial imaging is a safe and effective noninvasive method for the detection of myocardial ischemia or infarction in individuals with quadriplegia who are at increased risk for CAD.

Physical activity and its association with plasma lipids and lipoproteins in elderly women

The association of physical activity to plasma lipid and lipoprotein levels was examined cross-sectionally in 634 elderly, postmenopausal women whose mean age was 70.7 years. Leisure-time physical activity in kilocalories per week was assessed by the Paffenbarger Questionnaire, a composite index of sports/recreation, stair climbing, and walking. Subjects were categorized by tertile of kilocalories per week from total physical activity, number of flights of stairs climbed, and number of blocks walked. After adjustment for age, body mass index, education, and oral estrogen use, no significant differences were noted in total cholesterol, high-density-lipoprotein cholesterol (HDL-C), HDL2-C, HDL3-C, low-density-lipoprotein cholesterol (LDL-C), or triglycerides across tertile of total activity or number blocks walked. Total cholesterol was significantly different across tertile of number of flights of stairs climbed (P < 0.05), and only a borderline association was noted with LDL-C (P < 0.08). The study suggests that leisure-time physical activity, as measured by the Paffenbarger Questionnaire, is not associated with a favorable lipid profile in elderly, postmenopausal women. Failure to find an association may reflect the relatively small number of women who engaged in moderate- or high-intensity activity.

Lipid profiles in spinal cord injury

Measurement of blood levels of total cholesterol and lipoproteins (HDL and LDL) were conducted on 96 men with spinal cord injury, 46 paraplegics and 50 quadriplegics. All these patients were studied in the stabilized phase of the disease as a follow up to the rehabilitation process. The study was designed to compare results with a normal, able bodied population and to investigate if any abnormal finding could be related to the age at onset of the spinal cord injury, the duration of the disease or the level of the lesion. Compared to the normal, able bodied population, this study indicates that patients with a spinal cord injury do not have higher levels of cholesterol or LDL, nor lower levels of HDL. Levels of total cholesterol increase with aging, as in the normal population, but have no relation to the duration of the disease or the level of the lesion. Blood levels of HDL and LDL do not seem to be related either to the duration of the disease or to the level of the lesion.

Depressed serum high density lipoprotein cholesterol levels in veterans with spinal cord injury

Cardiovascular diseases are the most frequent cause of death among persons with spinal cord injury (SCI), and these diseases are reported to occur prematurely in the disabled compared to the able bodied population. The mechanism of accelerated coronary heart disease (CHD) in persons with SCI may be partially explicable on the basis of the lipoprotein profile. We performed fasting lipoprotein determinations on 100 veterans with SCI, 50 with paraplegia and 50 with quadriplegia, and 50 veteran controls. The mean age of the subjects with SCI was 47.8 +/- 1.4 years with a duration of injury of 16.3 +/- 1.2 years. The mean serum high-density lipoprotein (HDL) cholesterol was depressed in subjects with paraplegia or quadriplegia compared to controls (37 +/- 1 or 40 +/- 1 versus 48 +/- 2 mg/dL, p < 0.0001). Although serum total cholesterol was lower (p < 0.01) in subjects with SCI than in controls, there was no significant difference in mean serum low-density lipoprotein (LDL) cholesterol. Thirty-seven percent of subjects with SCI have serum HDL cholesterol levels less than 35 mg/dL with no significant difference in lipoprotein distribution between high and low cord lesions. Eighteen percent of individuals with SCI have an absolute elevation of LDL cholesterol (greater than 160 mg/dL). About 40% of those with SCI and LDL cholesterol levels between 130 and 160 mg/dL also have serum HDL cholesterol values below 35 mg/dL, all of whom would have their serum HDL cholesterol level undetected if lipoprotein profiles were performed according to present recommendations--that is, only if the serum total cholesterol is elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

The serum lipoprotein profile in veterans with paraplegia: the relationship to nutritional factors and body mass index

Individuals with spinal cord injury have a shortened life expectancy, with coronary heart disease as a leading cause of death. Identifying potentially reversible risk factors would be expected to be of value in the long-term care of the person with a spinal cord injury. We addressed the relationships among diet, body mass index, and serum lipid levels in 28 veterans with paraplegia compared to 52 age-matched ambulatory veteran controls. There are no significant differences in body mass index or in total caloric, saturated fat, or cholesterol intake between those with paraplegia and the control group. The serum HDL cholesterol level is significantly lower in those with paraplegia compared to the control group (35 +/- 2 vs 49 +/- 2 mg/dL). There are no significant differences noted in serum total cholesterol, LDL cholesterol, or triglycerides between the groups. Total caloric intake decreases significantly with age in the control subjects but not in the subjects with paraplegia. Inverse correlations are found between serum HDL cholesterol and serum triglycerides levels both in those with paraplegia (r = -0.54, p less than 0.005) and in the controls (r = -0.42, p less than 0.001). In our group of subjects with paraplegia, serum lipid levels appear to be independent of dietary intake and body weight.

Risk factors for cardiovascular disease in chronic spinal cord injury patients

To establish whether the reported increased cardiovascular (CV) morbidity in spinal cord injury (SCI) patients is due to increased levels of established CV risk factors, we assessed overall CV risk in 102 consecutive patients aged 25-64 by calculation of a 'risk factor score' (RFS) derived from the MRFIT study (age, diastolic blood pressure (DBP), total cholesterol (TC) level, cigarettes/day, sex), obtaining a percentile position amongst an age and sex matched peer group from the 1983 Australian Risk Factor Prevalence Study. Chronic SCI patients had a very low overall percentile position of risk of 26.03 + 15.06 (mean +/- S.D.) and those patients with SCI for greater than 10 years had only a slightly higher risk position of 33.16 +/- 29.66. The low relative risk in SCI patients was due mainly to significantly lower DBP levels (67 +/- 13 mm hg), as TC levels (5.38 +/- 1.60 mmol/L) and cigarette consumption (31% smokers, mode 11-20/day) were similar to the control population (83 +/- 12 mmHg, 5.68 +/- 1.2 mmol/L, 28% smokers, mode 11-20/day, respectively). As other known risk factors such as lipoprotein cholesterol fractions were not included in the RFS index, these were measured in 327 consecutive SCI patients. HDL cholesterol levels, which are negatively correlated with CV risk, were significantly lower in SCI patients (1.12 +/- 0.30 mmol/L) compared to controls (1.35 +/- 0.35 mmol/L) and those patients more than 10 years post SCI had still lower levels (1.02 +/- 0.40). These data suggest that the reported increased incidence of CV disease in SCI patients is unexplained by increases in BP, TC or smoking. However, low HDL levels may contribute to CV risk and the role of other risk factors such as increased vascular reactivity remain to be established.

The acute effect of 30 min of moderate exercise on high density lipoprotein cholesterol in untrained middle-aged men

Fifteen middle-aged, untrained (defined as no regular exercise) men (mean age 49.9 years, range 42-67) cycled on a cycle ergometer at 50 rpm for 30 min at an intensity producing 60% predicted maximum heart rate [(fc,max), where fc,max = 220 - age]. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglyceride (Tg) concentrations were measured from fasting fingertip capillary blood samples collected at rest, after 15 and 30 min of exercise, and at 15 min post-exercise. The mean HDL-C level increased significantly from the resting level of 0.85 mmol.l-1 to 0.97 mmol.l-1 (P < 0.05) after 15 min of exercise, increased further to 1.08 mmol.l-1 (P < 0.01) after 30 min of exercise and remained elevated at 1.07 mmol.l-1 (P < 0.01) at 15 min post-exercise. These increases represented changes above the mean resting level of 14.1%, 27.1% and 25.9% respectively. The HDL-C/LDL-C ratio increased significantly from a resting ratio of 0.20 to 0.26 after 30 min of exercise (P < 0.01) and to 0.24 at 15 min post-exercise (P < 0.05). The mean Tg level increased significantly from a resting level of 0.88 mmol.l-1 to 1.05 mmol.l-1 after 15 min, and to 1.06 mmol.l-1 after 30 min of exercise (P < 0.05 at each time). The TC/HDL-C ratio decreased significantly (P = 0.05) after 30 min of exercise and at 15 min post-exercise by 18.8% and 14%, respectively. No significant changes were observed in the levels of TC or LDL-C over time.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of insulin and body fat in associations of physical activity with lipids and lipoproteins in a biethnic population. The San Luis Valley Diabetes Study

It has been postulated that the positive effects of physical activity on high density lipoprotein cholesterol (HDL-C) and HDL-C subfraction 2 (HDL-C2) are mediated through insulin action because increased activity lowers insulin levels and lower insulin levels are associated with higher HDL-C. These relations were evaluated in a rural population of Hispanic and non-Hispanic white (NHW) adults in Colorado. Included were 138 men and 152 women with normal glucose tolerance confirmed by World Health Organization criteria. Total physical activity was assessed by 7-day recall interviews. No significant associations were observed among women. Among men, activity was inversely associated with fasting insulin (r = -0.17, p less than 0.05). From analysis of covariance models including the interaction term activity x ethnicity, total HDL-C was 43.4 mg/dl (95% confidence interval [CI] = 39.1, 47.7) in the low tertile of activity and 50.4 mg/dl (95% CI = 46.3, 54.5) in the high tertile for NHW men, after adjustment for fasting insulin, fasting glucose, body mass index (BMI), waist to hip ratio (WHR), and age. For Hispanic men, adjusted HDL-C was 43.4 mg/dl (95% CI = 38.6, 48.2) and 49.1 mg/dl (95% CI = 44.0, 54.2) in the low and high tertiles, respectively. Adjusted HDL-C2 levels were 52% higher in the most compared with the least active NHW men, whereas there was no difference by activity for Hispanic men. Higher adjusted mean levels of HDL-C3 were observed for the high compared with the low activity tertile in both ethnic groups. Ethnicity-specific models showed that for NHW men, activity explained 12% (p = 0.01), fasting insulin explained 5% (p = 0.05), and BMI explained 6% (p = 0.04) of the variability in total HDL-C, after adjustment for fasting glucose, WHR, and age. These models confirmed that effects of insulin and body fat did not explain the observed associations between activity and total HDL-C and its subfractions.

The prevalence of hypertension, ischaemic heart disease and diabetes in traumatic spinal cord injured patients and amputees

The clinical impression that spinal cord injured and traumatic lower limb amputees are more prone to develop degenerative diseases was investigated by comparing the prevalence of hypertension, ischaemic heart disease, and diabetes mellitus in these two patient groups with the prevalence of these diseases among a group of healthy age-matched controls. Seventy seven spinal cord injured patients and 53 amputees fulfilled the criteria for inclusion in this study. Our results show a significant increased incidence of hypertension and ischaemic heart disease among those with spinal cord injuries compared with their controls; and among the amputees, a significant increased incidence of ischaemic heart disease and of diabetes mellitus.

Physical activity and coronary heart disease in middle-aged and elderly men: the Honolulu Heart Program

The relationship of physical activity to the development of definite coronary heart disease was examined separately in middle-aged (45-64 years) and elderly men (65-69 years) participating in the Honolulu Heart Program. After 12 years of follow-up, results indicate that increased levels of physical activity reported at study entry were inversely related to the risk of definite coronary heart disease in both age groups. In particular, among those aged 45 to 64 years, the rate of definite coronary heart disease in men who led active life styles was 30 per cent lower than the rate experienced by those who were less active (relative risk, 0.69; 95% confidence interval, 0.53, 0.88). In those older than 64 years, the rate of definite coronary heart disease in active men was less than half the rate experienced by those who led more sedentary life styles (relative risk, 0.43; 95% CI, 0.19, 0.99). These results continued to hold up when controlling for several cardiovascular risk factors and potentially confounding variables, supporting earlier observations that physical activity is beneficial in middle-age, and further suggesting that benefits may extend to the elderly male population as well.

Changes in plasma lipids and apoproteins associated with physical training in middle-aged sedentary men

The effect of endurance training on plasma lipoproteins was investigated in 27 healthy sedentary men between the ages of 20 and 55 years. During the first 4 months of the study, 13 of them (group A) participated in a training program (3 hours/wk), whereas the others served as control subjects (group B). At the end of this period the control subjects also underwent a 4-month training program. In both groups the training significantly increased physical working capacity at a heart rate of 130 bpm (PWC130), whereas it decreased the resting heart rate (p less than 0.05). Concomitantly with this improvement in cardiorespiratory fitness, a significant increase in the high-density lipoprotein (HDL) cholesterol concentration was observed (p less than 0.01); this was due to an increase in both HDL2 beta and HDL2 alpha + 3 cholesterol concentrations. The plasma total and HDL-apoprotein AI and apoprotein AII concentrations were not significantly affected by the training. Significant decreases in plasma triglyceride (p less than 0.05), very-low-density lipoprotein cholesterol (p less than 0.05), and low-density lipoprotein (LDL) cholesterol (p less than 0.001) concentrations were also observed, but only in group B, which showed a much greater increase in PWC130 at the end of the training period than group A; the decrease in the LDL cholesterol concentration in this group was accompanied by a slight decrease in the LDL-apoprotein B concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipoprotein subfractions of runners and sedentary men

Serum concentrations of lipoprotein mass by flotation rate were measured in 12 long-distance runners and 64 sedentary men by analytic ultracentrifugation. The runners had significantly lower serum mass concentrations of the smaller, denser low-density lipoprotein particles of flotation rates Sf 0-7 (including the LDL-II, LDL-III, and LDL-IV subspecies), very-low-density lipoprotein (VLDL) particles of Sf 20-400, and high-density lipoprotein (HDL) particles of flotation rates F1.20 0-1.5 (predominantly the HDL3 subspecies), and higher serum mass concentrations of HDL particles with flotation rates between F1.20 2.0-9.0 (including HDL2a and HDL2b and less dense particles belonging to HDL3) than did sedentary men. Lipoprotein lipase activity was higher, and hepatic lipase activity was lower in runners than in the sedentary men. Thus, the effects of endurance exercise training to lower LDL may be specific to the smaller, denser LDL particle region. Similarities in the lipoprotein mass profiles of the runners and the low-risk profiles of sedentary, middle-aged women suggest the effects of common metabolic factors possibly leading to reduced risk of coronary artery disease.

Physical activity and health: need to define the required stimulus

Exercise is frequently recommended as part of a comprehensive program of prevention, treatment or rehabilitation of chronic degenerative disease. General guidelines on prescribing exercise are based more on the characteristics of exercise required to improve physical performance than on preventing disease. Most exercise regimens are evaluated according to their effect on aerobic power or endurance. Health benefits of exercise may occur in conjunction with an improvement in physical performance capacity, but some benefits appear to be achieved by exercise that normally does not lead to improved physical fitness. Health benefits may occur as a result of repeated acute responses to exercise (but without producing a training effect) and by frequent performance of low intensity exercise (inadequate for increasing fitness). Psychological benefits may also be derived by the process of exercising. The persons who benefit most from an increase in exercise are the very inactive because the detrimental health-related consequences of extreme inactivity are rapidly reversed. There is less evidence that an increase in exercise by the already active person results in significant health benefits.

Beta-blocker induced changes in the cholesterol: high-density lipoprotein cholesterol ratio and risk of coronary heart disease

The lowering of blood pressure with beta-blocking drugs has had a low impact on coronary heart disease (CHD) mortality and the question has been raised whether adverse changes in plasma lipoproteins offset the benefits of blood pressure reduction. Comparison of plasma lipoprotein concentrations in hypertensive patients treated with commonly used beta-blockers with lipoprotein concentrations in patients with coronary heart disease shows that these drugs cause clinically important shifts in the cholesterol ratio [total cholesterol (TC): high-density lipoprotein cholesterol (HDLC)] and reductions in the atheroprotective lipoprotein HDLC. The magnitude of these changes is sufficient to increase the risk of heart attack two- to four-fold depending on the initial cholesterol ratio and the duration of treatment. Only beta-blockers with marked intrinsic sympathomimetic agonist activity (pindolol) or combined alpha-beta-blocking properties (Labetalol) appear free of adverse effects on plasma lipoproteins and triglycerides. Chronic treatment with other beta-blockers should be accompanied by cholesterol and HDLC measurements at the beginning of therapy. Plasma lipoprotein measurements at 3-6 month intervals seem mandatory in patients with cholesterol values greater than 6 mmol/1 (230 mg/dl) and (TC):HDLC ratios above 5 at the start of treatment. The risk of a coronary event must be regarded as unacceptable when the cholesterol ratio exceeds a critical value of about 6. Further controlled studies are needed to evaluate the effects of beta-blockers in hypertension when administered for periods of up to a year or more. More information is required on the behaviour of lipoprotein subspecies and apoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)