The effects of heavy load carriage on physiological responses to graded exercise.

PURPOSE: Many emergency response occupations require heavy load carriage with backpacks. The purpose of this experiment was to study the effects of heavy load carriage on physiological responses and performance during graded exercise. METHODS: Fifty males (age: 28 ± 6 years, height: 182.8 ± 6.2 cm, mass: 85.4 ± 12.1 kg) provided written informed consent before completing two randomly ordered graded exercise tests to measure ventilatory threshold and peak oxygen consumption (˙VO2peak). During the loaded test, each subject carried a correctly sized and fitted 80 L backpack weighing 25 kg. Mass, volume and load distribution were consistent between all packs. Modified Balke treadmill tests were completed by walking at 1.5 m s(−1) with stage increases of 2% grade until exhaustion. RESULTS: Analysis revealed a small but significant decrease in ˙VO2 at ventilatory threshold (3.9%) and peak exercise (2.5%) under load. Power output at ventilatory threshold and ˙VO2peak were significantly decreased by 23.6 and 11.1%, respectively, and test duration was reduced by 29.8% in the loaded condition. CONCLUSIONS: While heavy load carriage had relatively small effects on physiological responses at ventilator threshold and peak exercise, the reductions in power output and test duration were more substantial. Despite the absolute mass of the pack and the large range of subject size, the only change in performance associated with body size was test duration. These results have implications for evaluation of fitness for duty in occupations where heavy load carriage is required.

The association between cardiorespiratory fitness and abdominal adiposity in postmenopausal, physically inactive South Asian women.

In South Asians, a unique obesity phenotype of high abdominal fat is associated with increased cardiovascular risk. Low cardiorespiratory fitness (CRF) is associated with abdominal fat and an increased risk of cardiovascular disease. The purpose of this paper is to determine whether CRF as assessed by VO2 peak, in post-menopausal South Asian women, was associated with body fat distribution and abdominal fat. Physically inactive post-menopausal South Asian women (n = 55) from the Greater Vancouver area were recruited and assessed from January to August 2014. At baseline, VO2 peak was measured with the Bruce Protocol, abdominal fat with CT imaging, and body composition with dual energy X-ray absorptiometry. ANOVA was used to assess differences in subcutaneous abdominal adipose tissue (SAAT), visceral adipose tissue (VAT) and total abdominal adipose tissue (TAAT) between tertiles of CRF. Bivariate correlation and multiple linear regression analyses explored the association between VO2 peak with SAAT, VAT, TAAT and body composition. Models were further adjusted for body fat and body mass index (BMI). Compared to women in the lowest tertile of VO2 peak (13.8-21.8 mL/kg/min), women in the highest tertile (25.0-27.7 mL/kg/min) had significantly lower waist circumference, BMI, total body fat, body fat percentage, lean mass, SAAT, VAT and TAAT (p < 0.05). We found VO2 peak to be negatively associated with SAAT, VAT and TAAT, independent of age and body fatness but not independent of BMI. Further research is necessary to assess whether exercise and therefore improvements in CRF would alter SAAT, VAT and TAAT in post-menopausal South Asian women.

The association between physical activity and liver fat after five years of follow-up in a primary prevention multi-ethnic cohort.

OBJECTIVE: Excess liver fat (LF) is associated with dyslipidemia, insulin resistance and cardiovascular disease. Evidence suggests that there is an independent relationship between physical activity (PA) and LF although little is known of the role of PA intensity in reducing LF. The purpose was to evaluate whether meeting PA guidelines, the amount of PA and the intensity of PA at baseline were associated with LF after five-years. METHODS: Men and women (n=478) living in Vancouver, Canada of Aboriginal, Chinese, European or South Asian background completed baseline measurements in 2004-2005. Liver fat was assessed using CT scans at 5-year follow-up, and PA using a PA questionnaire at baseline as well as demographics and anthropometry. RESULTS: In separate unadjusted models, meeting moderate-vigorous PA (MVPA) guidelines (p=0.009), vigorous PA (p=0.002) and MVPA (p=0.017) but not moderate PA (p=0.068) was predictive of LF at five years (p=0.009). In multiple linear regression models, when adjusted for covariates, meeting MVPA guidelines and MVPA with LF at five years was no longer significant (p>0.05) while vigorous PA remained significant (p=0.021). CONCLUSION: Meeting PA guidelines through MVPA may not be adequate to prevent the accumulation of LF and PA guidelines may require revision. Vigorous PA should be encouraged to prevent LF accumulation.

Preadult onset vs. adult onset of major depressive disorder: a replication study.

OBJECTIVE: In the first 1500 participants with major depressive disorder (MDD) that entered the sequenced treatment alternatives to relieve depression (STAR*D) study, those with preadult onset MDD were more likely to be women and to have a more chronic, severe and disabling form of depression than those with adult onset MDD. This study seeks to replicate these findings. METHOD: The second wave of STAR*D enrollees included 2541 out-patients with MDD, divided into preadult (before age 18) and adult (age 18 or later) onset groups. RESULTS: Participants with a preadult onset of MDD (38%) were younger, ill for longer and more likely to be women than those with adult onset MDD (62%). After adjusting for age, duration of illness and gender, participants with preadult onset MDD also had higher rates of family history of depression, more past suicide attempts, and lower rates of obsessive compulsive and panic disorder. CONCLUSION: Preadult onset MDD may be associated with a more familial form of depression with more suicidality than adult onset MDD.

Effect of chromium supplementation and exercise on body composition, resting metabolic rate and selected biochemical parameters in moderately obese women following an exercise program.

OBJECTIVE: To investigate the effect of chromium picolinate (CP) supplementation on body composition, resting metabolic rate (RMR), selected biochemical parameters and iron and zinc status in moderately obese women participating in a 12-week exercise program. METHODS: Forty-four women, 27 to 51 years of age, were randomly assigned to two groups based on their body mass index. Subjects received either 400 microg/day of chromium as a CP supplement or a placebo in double-blind fashion and participated in a supervised weight-training and walking program two days per week for 12 weeks. Body composition and RMR were measured at baseline, 6 and 12 weeks. Selected biochemical parameters and iron and zinc status were measured at baseline and 12 weeks. RESULTS: Body composition and RMR were not significantly changed by CP supplementation. No significant differences in fasting plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or in iron and zinc indices were found between the two groups over time. Serum total cholesterol concentration significantly decreased (p = 0.0016) over time for all subjects combined, probably as a result of the exercise training. Exercise training significantly reduced total iron binding capacity (TIBC) by 3% for all subjects combined (p = 0.001 1). CONCLUSIONS: Twelve weeks of 400 microg/day of chromium as a CP supplement did not significantly affect body composition, RMR, plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or iron and zinc indices in moderately obese women placed on an exercise program. The changes in serum total cholesterol levels and TIBC were a result of the exercise program.

Apolipoprotein-E and white-matter hyperintensities in late-life depression.

The authors conducted a follow-up study of 16 patients with late-life depression approximately 6 years after their initial assessment to evaluate the relationships between apolipoprotein-E (APO-E) status and white-matter hyperintensities (WMH). Ten patients had WMH at baseline, and four patients demonstrated an increase in WMH size over time. Three of four patients with the APO-E epsilon 4 allele demonstrated an increase in WMH over time, and only 1 of 12 patients without an epsilon 4 allele had an increase in WMH. Three of four patients with APO-E epsilon 4 allele developed a chronic course of major depression at follow-up. Patients with APO-E epsilon 4 had a higher number of depressive episodes and lower age at onset. APO-E may be a risk factor for cerebrovascular disease associated with late-life depression and may affect the clinical characteristics and disease course of depression.

Performance of older depressed patients on two cognitive malingering tests: false positive rates for the Rey 15-item memorization and dot counting tests.

To our knowledge, no investigations have been undertaken to determine whether depression impacts performance on two commonly used tests to detect malingering of cognitive symptoms, the Rey 15-item Memorization Test and the Rey Dot Counting Test. This is a critical issue because of the high rate of depressive symptoms in patients with neurological conditions. It was hypothesized that depressed individuals, especially those with more severe depression, might be at risk for failing the tests, because these patients exhibit mild deficits in mental speed, visual perceptual/spatial skills, and visual memory, abilities required for successful completion of the malingering tests. However, examination of test performance in 64 older participants with major depression generally revealed very low false positive rates for most test scores, and severity of depression was unrelated to test scores. These results add to accumulating data supporting the validity of these cognitive malingering tests by documenting few false positive identifications.

Clinical and neuroradiologic features associated with chronicity in late-life depression.

The authors conducted a 6-year follow-up of 16 patients with late-life depression to evaluate the relationships between clinical and neuroradiologic variables and disease outcome. Patients had a comprehensive neuropsychiatric evaluation and magnetic resonance imaging (MRI) at baseline and follow-up. Eight of the 16 developed a chronic course of unremitting major depression sufficient to cause significant psychosocial impairment. Six patients with a chronic course and four patients with a non-chronic course of depression had white matter hyperintensities (WMH) on MRI at baseline. Four patients whose WMH increased in size over time developed a chronic unremitting course of depression. No patients with non-chronic depression had large areas of WMH at baseline or exhibited increased WMH size over time. Chronic depression was associated with severity of cerebrovascular risk factors, apathy, and poor quality of life. Treatment and prevention of cerebrovascular disease may improve the outcome of late-life depression.

REM sleep in depression is influenced by ethnicity.

The influence of ethnicity on the manifestation of EEG sleep changes in depression was studied in 95 patients (21 African-Americans [AA], 17 Asians [AS], 37 Caucasians [C] and 20 Hispanics [H]) with unipolar major depression. Subjects were studied twice for 2 consecutive nights. On the second night of each 2-night session, placebo or scopolamine (1.5 microg/kg, IM, at 23.00 h) was administered. On the baseline (placebo) night, sleep architecture, sleep continuity and rapid eye movement (REM) sleep variables were generally comparable among the groups. However, REM sleep was less in AA and AS subjects than in C and H subjects. Furthermore, the distribution of REM sleep over the course of the night in AA and AS subjects differed significantly from that in the C and H groups. Although scopolamine significantly affected sleep continuity and REM sleep measures, no significant differential effects of scopolamine were observed. Because many antidepressants suppress REM sleep, the differences in baseline REM sleep observed might be related to the greater sensitivity of some ethnic-minority depressed patients to pharmacotherapy.

Relationship of age, age at onset, and sex to depression in older adults.

The authors investigated the relationships among factors of age, age at onset, and sex in depressed older adults. A group of 96 outpatients (mean age, 60) diagnosed with late-(LOD) and early-onset (EOD) major depression were assessed for severity of depression and underwent magnetic resonance imaging (MRI). The MRI scans were rated for severity of white-matter hyperintensities (WMH) and ventricle-to-brain ratio (VBR). LOD was associated with increased amounts of WMH, larger VBR, and history of hypertension. Men were more severely depressed than women, with higher rates of neurovegetative signs and history of smoking. Age correlated with increased VBR and WMH, history of hypertension, history of percipitants for the current episode, and lack of social support. Results suggest that a subgroup of men may be more at risk for LOD associated with WMH and that sex and age at onset need to be considered in future studies.

Base rates of "impaired" neuropsychological test performance among healthy older adults.

Base rates of deficient neuropsychological test performance were evaluated among 132 neurologically healthy older normal adults using a variety of measures commonly employed in the "flexible-battery"approach to neuropsychological assessment. Subjects were divided into three age groups (50 to 59, 60 to 69, and 70 to 79 years). Despite the healthy status of our sample, most tests yielded at least some proportion of subjects earning scores in the borderline and impaired ranges (1.3 and 2.0 standard deviations below the age-group mean, respectively). Across the battery of measures, 73% of subjects earned a borderline score on at least one measure, and 20% of subjects earned at least two scores in the impaired range on separate tests. The proportion of subjects consistently earning borderline or impaired scores across multiple measures within specific cognitive domains was generally lower. Results illustrate the problems in interpreting isolated low scores, and the need to consider false-positive base rates in drawing inferences from poor test performance.

Frontotemporal dementia: treatment response to serotonin selective reuptake inhibitors.

BACKGROUND: Patients with frontotemporal dementia (FTD) present initially with primarily behavioral rather than cognitive symptoms. Decreased serotonin receptor binding has been reported in the frontal lobes, temporal lobes, and hypothalamus in autopsy-proven FTD cases. This study tests the hypothesis that many of the behavioral symptoms of FTD (including disinhibition, depressive symptoms, carbohydrate craving, and compulsions) will respond to serotonin selective reuptake inhibitors (SSRIs). METHOD: Eleven subjects meeting the Lund-Manchester clinical, neuropsychological, and neuroimaging criteria for FTD were treated with SSRIs (fluoxetine, sertraline, or paroxetine). After 3 months, treatment responses for disinhibition, depressive symptoms, carbohydrate craving, and compulsions were evaluated prospectively without placebo control. RESULTS: After treatment, disinhibition, depressive symptoms, carbohydrate craving, and compulsions all showed improvement in at least half the subjects in which they had been present. One subject stopped sertraline treatment because of diarrhea, while another stopped paroxetine treatment due to increased anxiety. The presence of individual behavioral symptoms and also the response of each symptom to SSRIs were unrelated to cognitive impairment as measured by baseline Mini-Mental Status Examination (.07 < or = p < or = 1.00) [corrected]. CONCLUSION: The behavioral symptoms of FTD may improve after treatment with SSRIs. Future neurochemical studies and controlled pharmacologic trials may improve available treatments.

Differential response of rapid eye movement sleep to cholinergic blockade by scopolamine in currently depressed, remitted, and normal control subjects.

The degree of cholinergic dysregulation of sleep in adult depression was evaluated using scopolamine. On separate sessions, placebo and scopolamine (4.5 micrograms/kg, IM) were administered to 14 patients with unipolar major depression, 16 recovered/remitted patients, and 18 normal controls. Scopolamine increased rapid eye movement (REM) latency (RL), reduced REM activity (RA), REM density (RD), and REM duration, and increased the percentage of stage 4 sleep in all groups. There was a differential effect of scopolamine on RL, RA, and REM duration for the first REM period, and on percentage of stage 4 sleep. Whereas a primary cholinergic hyperactivity could account for the RA and RD responses, the response profile for RL was more compatible with reduced aminergic tone as the proximal cause of the cholinergic hyperactivity. Whether the sleep abnormalities observed in remitted patients reflect an underlying vulnerability for development or recurrence of depression, and/or a scar, remains to be determined.

Behavioral phenomenology in Alzheimer's disease, frontotemporal dementia, and late-life depression: a retrospective analysis.

Often patients in the early stages of Alzheimer's disease (AD), frontotemporal dementia (FTD), and late-life depression can be difficult to differentiate clinically. Although subtle cognitive distinctions exist between these disorders, noncognitive behavioral phenomenology may provide additional discriminating power. In 19 subjects with AD, 19 with FTD, 16 with late-life psychotic depression (LLPD), and 19 with late-life nonpsychotic depression (LLNPD), noncognitive behavioral symptoms were quantified retrospectively using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and compared using both a one-way ANOVA and a multivariate stepwise discriminant analysis, which utilized a jackknife procedure. The FTD group showed the highest mean total SCAN score, while the AD group showed the lowest. ANOVA showed significant differences in the mean total SCAN scores between the four diagnostic groups (P < .0001). With the discriminant analysis, the four disorders demonstrated different clusters of behavioral abnormalities and were differentiated by these symptoms (P < .0001). A subset of 14 SCAN item group symptoms was identified that collectively classified the following percentages of subjects in each diagnostic category: AD 94.7%, FTD 100%, LLPD 87.5%, and LLNPD 100%. These results indicate that AD, FTD, LLPD, and LLNPD were distinguished retrospectively by the SCAN without using cognitive data. Better definition of the longitudinal course of noncognitive behavioral symptoms in different dementias and psychiatric disorders will be valuable both for diagnosis and to help define behavioral syndromes that are associated with selective neuroanatomic and neurochemical brain pathology.

Clinical presentations of depression in African American and white outpatients.

The objective of this study was to compare the nature and severity of depressive symptoms in moderately depressed, medically healthy African American and White patients. Twenty age- and gender-matched subjects from each ethnic group who met criteria for a major depression were assessed with structured interviews, and their depression was evaluated with the Hamilton Depression Rating Scale (HAM-D). Overall severity of the depression was comparable between groups. When the individual HAM-D items were grouped into factors, Whites showed significantly more articulated/observed mood and anxiety symptoms, whereas African Americans had significantly more diurnal variation to their depression. There were no differences on other neurovegetative symptoms. These results are discussed in the context of past studies, which often used very heterogeneous populations not matched for socioeconomic status, and included those with comorbid psychiatric and medical illnesses. Although our sample size was relatively modest, the results suggest that clinicians should be aware of potential differences in symptom presentation when treating patients from different ethnic groups.

Neuropsychological deficits among older depressed patients with predominantly psychological or vegetative symptoms.

Depressed outpatients having primarily psychological or vegetative symptoms, as defined by the factor analytically developed Hamilton Depression Scale superfactors described by Rhoades and Overall (1983), were compared with similarly aged normal controls on a comprehensive neuropsychological battery. The vegetative group evidenced poorer performance than controls on several measures associated with right hemisphere functioning and on a task associated with executive functioning. In contrast, the psychological group did not significantly differ from controls on any measure, and had significantly better performance than the vegetative group on several tasks. These findings suggest that neuropsychological deficits associated with depression may be limited to those patients with primarily vegetative symptoms.

Cognition and white matter hyperintensities in older depressed patients.

OBJECTIVE: The authors compared amounts of white matter hyperintensity in late- and early-onset depressed patients and never-depressed older subjects, compared neuropsychological function in these groups, and investigated the association between white matter hyperintensities and cognitive function in depression. METHOD: Sixty currently depressed patients whose first depression occurred after age 50 years, 35 depressed patients over age 50 whose first depression occurred before age 35, and 165 nonpsychiatrically ill subjects over age 50 underwent magnetic resonance imaging (MRI) and neuropsychological evaluation. Areas of white matter hyperintensity were measured from MRI images. RESULTS: The late-onset patients had more white matter hyperintensity than either of the other groups. Compared to the nondepressed subjects, the patients had significantly lower scores in the cognitive domains of nonverbal intelligence, nonverbal memory, constructional ability, executive ability, and information processing speed. The cognitive abnormalities were mostly confined to the late-onset patients, and the presence of a large amount of white matter hyperintensity was associated with significantly poorer executive skills. However, most of the scores were not in the significantly impaired range. CONCLUSIONS: Large amounts of white matter hyperintensity are more frequent in patients with late-onsetdepression than in elderly subjects with early-onset or no depression. Both late- and early-onset elderly depressed patients show mild decrements in some "right hemisphere" cognitive skills; the late-onset subjects also show deterioration in information processing speed and executive functions. Patients with large amounts of white matter hyperintensity have significantly poorer executive function.

The evolving science of pharmacogenetics: clinical and ethnic perspectives.

The field of pharmacogenetics has witnessed remarkable progress during the past several decades. Clinical observations of severe toxic reactions and findings of dramatic interindividual as well as cross-ethnic differences in response to therapeutic agents have been instrumental in fostering advances of the field. Research on cytochrome P450 isozymes may be of particular importance to the field of psychiatry, because most psychotropics depend on these enzymes for their biotransformation. This article traces the progress of research in this area and highlights the importance of clinical and cross-ethnic observations in providing the impetus and direction for the field. Knowledge derived from this line of research is likely to make important contributions toward establishment of rational guidelines for psychopharmacotherapy. In addition, research on these enzymes may also have profound implications in regard to the pathogenesis of a number of major disorders, including several types of commonly encountered cancers, as well as neuropsychiatric problems, including Parkinson's disease, tardive dyskinesia, addiction, and drug-induced neurotoxicity.

Brain imaging, antidepressants, and ethnicity: preliminary observations.

Magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) using 99mTc-hexamethylpropylene amine oxime (HMPAO) evaluations were completed on African-American and Caucasian depressed patients prior to their participation in an antidepressant medication trial. The degree of white matter hyperintensities (WMH), ventricle-to-brain ratio (VBR), and uptake of HMPAO did not vary significantly between the groups. After 1 week of placebo run-in, patients received paroxetine in an 8-week, open-label, flexible-dose trial. Final dosages and side effects were similar between groups. There was a trend for the Caucasian patients to have a better treatment response, but the relatively small sample size makes this finding tentative. In general, there were no major differences in either baseline neuroimaging findings or response to paroxetine between these two ethnic groups.