C. Laird Birmingham

The incidence of co-morbidities related to obesity and overweight: A systematic review and meta-analysis

BackgroundOverweight and obese persons are at risk of a number of medical conditions which can lead to further morbidity and mortality. The primary objective of this study is to provide an estimate of the incidence of each co-morbidity related to obesity and overweight using a meta-analysis.MethodsA literature search for the twenty co-morbidities identified in a preliminary search was conducted in Medline and Embase (Jan 2007). Studies meeting the inclusion criteria (prospective cohort studies of sufficient size reporting risk estimate based on the incidence of disease) were extracted. Study-specific unadjusted relative risks (RRs) on the log scale comparing overweight with normal and obese with normal were weighted by the inverse of their corresponding variances to obtain a pooled RR with 95% confidence intervals (CI).ResultsA total of 89 relevant studies were identified. The review found evidence for 18 co-morbidities which met the inclusion criteria. The meta-analysis determined statistically significant associations for overweight with the incidence of type II diabetes, all cancers except esophageal (female), pancreatic and prostate cancer, all cardiovascular diseases (except congestive heart failure), asthma, gallbladder disease, osteoarthritis and chronic back pain. We noted the strongest association between overweight defined by body mass index (BMI) and the incidence of type II diabetes in females (RR = 3.92 (95% CI: 3.10–4.97)). Statistically significant associations with obesity were found with the incidence of type II diabetes, all cancers except esophageal and prostate cancer, all cardiovascular diseases, asthma, gallbladder disease, osteoarthritis and chronic back pain. Obesity defined by BMI was also most strongly associated with the incidence of type II diabetes in females (12.41 (9.03–17.06)).ConclusionBoth overweight and obesity are associated with the incidence of multiple co-morbidities including type II diabetes, cancer and cardiovascular diseases. Maintenance of a healthy weight could be important in the prevention of the large disease burden in the future. Further studies are needed to explore the biological mechanisms that link overweight and obesity with these co-morbidities.

The use of BMI and waist circumference as surrogates of body fat differs by ethnicity.

Objective: To compare the prediction of percentage body fat using BMI and visceral adipose tissue (VAT) using waist circumference (WC) in individuals of Chinese, European, and South Asian origin.

Modification of the relationship between simple anthropometric indices and risk factors by ethnic background.

Current targets for body mass index (BMI) and waist circumference (WC) may not be appropriate for those of South Asian origin. The objectives of this study were to determine whether the relationship between BMI and WC with risk factors for cardiovascular disease (CVD) is the same for men and women of South Asian and European descent. Apparently healthy men and women of European (n = 88) and South Asian (n = 93) descent were recruited from 3 hospital communities and assessed for BMI, WC, waist-to-hip ratio (WHR), blood pressure (BP), lipids, insulin, glucose, and CRP. The study cohort was stratified by sex, and regression analyses were performed with individual risk factors as outcomes and ethnicity with either BMI or WC as predictors adjusting for age and height (WC only). BMI and WC were similar between the European and South Asian men and women. South Asian men had significantly higher values for total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), total cholesterol:high-density lipoprotein-cholesterol (HDL-C) and CRP, and significantly lower values of HDL-C. South Asian women had significantly higher values for TG, TC:HDL-C and CRP and significantly lower values of HDL-C, glucose, systolic BP and diastolic BP. In men, ethnicity was an independent predictor for all risk factors except for glucose and insulin, after adjusting for either BMI or WC independent of age and height. For women, ethnicity was an independent predictor for all risk factors except for total cholesterol (WC model only) and insulin (BMI model only), after adjusting for either BMI or WC independent of age and height. The relationship between BMI or WC and risk factors is such that men and women of South Asian descent present with a more adverse risk profile than those of European descent at the same BMI and/or WC.

Visceral Adipose Tissue, a Potential Risk Factor for Carotid Atherosclerosis Results of the Multicultural Community Health Assessment Trial (M-CHAT)

Background and Purpose— The association between abdominal obesity and atherosclerosis is believed to be due to excess visceral adipose tissue (VAT), which is associated with traditional risk factors. We hypothesized that VAT is an independent risk factor for atherosclerosis. Methods— Healthy men and women (N=794) matched for ethnicity (aboriginal, Chinese, European, and South Asian) and body mass index range (<25, 25 to 29.9, or ≥30 kg/m2) were assessed for VAT (by computed tomography scan), carotid atherosclerosis (by ultrasound), total body fat, cardiovascular risk factors, lifestyle, and demographics. Results— VAT was associated with carotid intima-media thickness (IMT), plaque area, and total area (IMT area and plaque area combined) after adjusting for demographics, family history, smoking, and percent body fat in men and women. In men, VAT was associated with IMT and total area after adjusting for insulin, glucose, homocysteine, blood pressure, and lipids. This association remained significant with IMT after further adjustment for either waist circumference or the waist-to-hip ratio. In women, VAT was no longer associated with IMT or total area after adjusting for risk factors. Conclusions— VAT is the primary region of adiposity associated with atherosclerosis and likely represents an additional risk factor for carotid atherosclerosis in men. Most but not all of this risk can be reflected clinically by either the waist circumference or waist-hip ratio measures.

Influence of dietary fat polyunsaturated to saturated ratio on energy substrate utilization in obesity

The effect of the polyunsaturated to saturated (P:S) ratio of dietary fat on preprandial and postprandial macronutrient oxidation was studied in normal-weight and obese individuals. Total thermogenic response and fat and carbohydrate oxidation rates were determined by duplicate respiratory gas exchange measurements after test breakfasts, in seven normal and eight overweight subjects who consumed self-selected diets containing fat of high or low P:S ratio. Dietary intake records and erythrocyte linoleic to oleic (L:O) acid ratio changes were used as indicators of dietary compliance. No diet- or weight-related differences were observed in resting fat or carbohydrate oxidation rates, or in protein-free basal energy expenditure. Obese subjects consuming low P:S ratio diets exhibited reduced (P less than .05) contribution of fat oxidation to the thermogenic response, compared with lean individuals consuming high or low P:S ratio diets. However, total calories associated with the thermogenic response, and total fat and carbohydrate oxidation after the test breakfasts, did not differ significantly across groups. These findings suggest that, in obesity, whole-body postprandial disposal of dietary fat is influenced by the long-chain fatty acid composition.

Shape- and weight-based self-esteem and the eating disorders

OBJECTIVES To determine the psychometric properties of the Shape- and Weight-Based Self-Esteem (SAWBS) Inventory in women with eating disorders, and to compare SAWBS scores in women who have eating disorders with women from psychiatric and normal control groups. METHOD Women with eating disorders (n = 48), women with other psychiatric disorders (n = 44), and undergraduate control women (n = 82) completed the SAWBS Inventory and measures of depression, self-esteem, and eating disorder symptomatology. Twenty women from the eating disorder group completed the SAWBS Inventory a second time 1 week later. RESULTS Similar to previous work in undergraduate samples, SAWBS scores were stable over 1 week, and demonstrated concurrent and discriminant validity in women with eating disorders. In between-group comparisons, SAWBS scores were higher among women with eating disorders than in either control group, even after controlling for age, socioeconomic status, body mass index, and self-esteem. A differing relationship between depression and SAWBS emerged as a function of group; SAWBS scores differed significantly among depressed, but not nondepressed women from the three groups. CONCLUSION The psychometric properties of the SAWBS Inventory were established in women with eating disorders. As expected, SAWBS scores were higher in women with eating disorders than in the control groups. Clinical implications of these findings are discussed.

Anorexia nervosa: Refeeding and hypophosphatemia

A case of anorexia nervosa (AN) is reported where heart failure occurred secondary to severe hypophosphatemia despite oral phosphate supplementation. We recommend starting patients with AN on oral phosphate when refeeding is begun, monitoring serum phosphate every 1 to 2 days for at least the first week of refeeding, and discontinuation of refeeding during phosphate supplementation should severe hypophosphatemia develop.

TELOMERE LENGTH AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE: EVIDENCE OF ACCELERATED AGING

benzodiazepine. Twenty-eight percent of patients were prescribed an NSAID, and 31% of these patients were not concomitantly prescribed an agent for gastric protection (e.g., proton pump inhibitor or misoprostol). Of patients prescribed an NSAID, 61% were also prescribed a daily diuretic, 27% were concurrently prescribed an ACEI or ARB, and 21% were prescribed a daily diuretic and an ACEI or ARB. Data from this cross-sectional survey on prescribing at community-based primary care academic training sites provided valuable information about local practice patterns and demonstrated that use of benzodiazepines and NSAIDs remains prevalent in older adults. There are several potential reasons for this, including limited expertise in geriatric pharmacotherapy; established practice patterns and comfort with those patterns; and conversely, limited practical experience with the recommended alternatives. Because other studies have shown that although practice patterns remain suboptimal with regard to prescribing for older adults, changing provider practice patterns is difficult. It remains to be determined whether interventions based on local practice data can substantially influence change in provider prescribing patterns on a community-wide scale.

Appropriateness of current thresholds for obesity-related measures among Aboriginal people

Background: Despite the high prevalence of obesity and diabetes in the Canadian Aboriginal population, it is unknown whether the current thresholds for body mass index and waist circumference derived from white populations are appropriate for Aboriginal people. We compared the risk of cardiovascular disease among Canadian Aboriginal and European populations using the current thresholds for body mass index and waist circumference. Methods: Healthy Aboriginal (n = 195) and European (n = 201) participants (matched for sex and body mass index range) were assessed for demographic characteristics, lifestyle factors, total and central adiposity and risk factors for cardiovascular disease. Among Aboriginal and European participants, we compared the relation between body mass index and each of the following 3 factors: percent body fat, central adiposity and cardiovascular disease risk factors. We also compared the relation between waist circumference and the same 3 factors. Results: The use of body mass index underestimated percent body fat by 1.3% among Aboriginal participants compared with European participants (p = 0.025). The use of waist circumference overestimated abdominal adipose tissue by 26.7 cm2 among Aboriginal participants compared with European participants (p = 0.007). However, there was no difference in how waist circumference estimated subcutaneous abdominal and visceral adipose tissue among the 2 groups. At the same body mass index and waist circumference, we observed no differences in the majority of cardiovascular disease risk factors among Aboriginal and European participants. The prevalence of dyslipidemia, hypertension, impaired fasting glucose and metabolic syndrome was similar among participants in the 2 groups after adjustment for body mass index, waist circumference, age and sex. Interpretation: We found no difference in the relation between body mass index and risk of cardiovascular disease between men and women of Aboriginal and European descent. We also found no difference between waist circumference and cardiovascular disease risk among these groups. These data support the use of current anthropometric thresholds in the Canadian Aboriginal population.

Continuing medical education article

SummaryMagnesium plays an important role as a cofactor in many of the body’s critical functions and reactions. A deficiency or excess of extracellular magnesium can produce significant signs and symptoms. Hypomagnesaemia is a common finding in hospitalised patients, especially those in critical care areas. Anaesthetising hypomagnesaemic patients may exacerbate pre-existing cardiovascular disease and increase the risk of perioperative dysrhythmias. A low serum magnesium level usually suggests a total body deficiency of magnesium. Treatment of magnesium deficiency is by parenteral magnesium and should be instituted prior to surgery.Hypermagnesaemia is often iatrogenic and is more likely in patients with renal dysfunction who are receiving oral or parenteral magnesium. The specific antidote is intravenous calcium. Anaesthetised patients with high serum magnesium levels are at risk from hypotension, potentiation of non-depolarising neuromuscular blockers, postoperative respiratory failure and cardiac arrest.Magnesium plays an important role as a cofactor in many of the bodys critical functions and reactions. A deficiency or excess of extracellular magnesium can produce significant signs and symptoms. Hypomagnesaemia is a common finding in hospitalised patients, especially those in critical care areas. Anaesthetising hypomagnesaemic patients may exacerbate pre-existing cardiovascular disease and increase the risk of perioperative dysrhythmias. A low serum magnesium level usually suggests a total body deficiency of magnesium. Treatment of magnesium deficiency is by parenteral magnesium and should be instituted prior to surgery. Hypermagnesaemia is often iatrogenic and is more likely in patients with renal dysfunction who are receiving oral or parenteral magnesium. The specific antidote is intravenous calcium. Anaesthetised patients with high serum magnesium levels are at risk from hypotension, potentiation of non-depolarising neuromuscular blockers, postoperative respiratory failure and cardiac arrest.