Intentional weight loss, blood lipids and coronary morbidity and mortality

PURPOSE OF REVIEW: Although weight reduction has been recommended to reduce cardiovascular risk, studies on the association between weight loss and coronary morbidity and mortality show conflicting results. This review summarizes findings from large studies examining this issue and accentuates the importance of carrying out additional well-designed research. RECENT FINDINGS: Many observational studies report that weight loss in older men and women is associated with increased cardiovascular morbidity and mortality. Recent studies suggest that this association may arise from the confounding effect of preexisting disease. Many studies do not report whether weight loss is intentional or unintentional. Unintentional weight loss may mask beneficial changes in cardiovascular risk due to intentional weight loss. In addition to issues related to the cause of weight loss, use of reported rather than measured weight may bias the results of large studies. However, one recent observational study with a methodology aimed at overcoming these limitations found that individuals who intentionally lost weight experienced a decreased coronary risk. SUMMARY: Weight reduction in overweight individuals is not universally associated with good health. This is true even if the weight loss results in normal body mass index. Reports of increased coronary risk associated with intentional weight loss may be explained by comorbidities that are also associated with weight loss. Individuals who are overweight and at high coronary risk may benefit from professionally supervised dieting and avoiding regain of lost weight. Clinical trials on cardiovascular outcomes in individuals who lose weight under supervised dieting are needed to assess this recommendation definitively.     

Green tea, anti-diabetic or diabetogenic: a dose response study

Present study was conducted to clarify whether lower or higher dietary dose of green tea is beneficial for the reduction of risk of type 2 diabetes. Five weeks old male SD rats were fed high fat diet for 2 weeks then divided into 4 groups of 8 animals as Normal Control (NC), Diabetic Control (DBC), Green Tea Low (GTL, 0.5%, Green Tea High (GTH, 2.0%) groups. Diabetes was induced by intra-peritoneal (i.p) injection of STZ (40 mg/kg BW) in all animals except NC group. After 4 weeks feeding of experimental diets, serum fasting blood glucose was not decreased but relatively increased in both green tea fed groups compared to DBC group. Serum insulin concentration was significantly (p< 0.05) increased in GTL group but not in GTH group when compared with DBC group. Serum lipids were significantly decreased in GTH group but not in GTL group compared to DBC group. Intra-peritoneal glucose tolerance test, blood HbA1c, liver weight, and liver glycogen level were not influenced by the feeding of green tea containing diets. Data of this study suggest that lower dose of green tea is insulinotropic when higher dose is hyperglycemic but hypolipidemic at least in this experimental condition.     

Midline episiotomy and anal incontinence: retrospective cohort study

ObjectiveTo evaluate the relation between midline episiotomy and postpartum anal incontinence.DesignRetrospective cohort study with three study arms and six months of follow up.SettingUniversity teaching hospital.ParticipantsPrimiparous women who vaginally delivered a live full term, singleton baby between 1 August 1996 and 8 February 1997: 209 who received an episiotomy; 206 who did not receive an episiotomy but experienced a second, third, or fourth degree spontaneous perineal laceration; and 211 who experienced either no laceration or a first degree perineal laceration.ResultsWomen who had episiotomies had a higher risk of faecal incontinence at three (odds ratio 5.5, 95% confidence interval 1.8 to 16.2) and six (3.7, 0.9 to 15.6) months postpartum compared with women with an intact perineum. Compared with women with a spontaneous laceration, episiotomy tripled the risk of faecal incontinence at three months (95% confidence interval 1.3 to 7.9) and six months (0.7 to 11.2) postpartum, and doubled the risk of flatus incontinence at three months (1.3 to 3.4) and six months (1.2 to 3.7) postpartum. A non-extending episiotomy (that is, second degree surgical incision) tripled the risk of faecal incontinence (1.1 to 9.0) and nearly doubled the risk of flatus incontinence (1.0 to 3.0) at three months postpartum compared with women who had a second degree spontaneous tear. The effect of episiotomy was independent of maternal age, infant birth weight, duration of second stage of labour, use of obstetric instrumentation during delivery, and complications of labour. ConclusionsMidline episiotomy is not effective in protecting the perineum and sphincters during childbirth and may impair anal continence.     

Effect of weight loss in adults on estimation of risk due to adiposity in a cohort study

The effect of overweight and obesity on the risk of fatal disease tends to attenuate with age. To evaluate whether this effect is partly attributable to disease-related weight loss, we examined the prebaseline history of weight loss and diseases associated with weight loss among adults enrolled in a cohort study. We conducted an analysis of 7,855 adult cohort members of the Adventist Health Study (AHS) I who had provided anthropometric data on surveys at baseline and 17 years prior to baseline. Among adults in the recommended range of BMI (19-25 kg/m(2)) at baseline we found that: (i) the prevalence of prebaseline weight loss of 5 kg/m(2) from an overweight or obese state was 20.4% and increased with age (12.6% for <65 years; 27.7% for 65-84 years; 36.7% for >85 years) and (ii) prebaseline weight loss of 5 kg/m(2) from an overweight or obese state was associated with diabetes (odds ratio (OR) = 2.91 95% confidence interval (CI) = (2.16, 3.93)), coronary heart disease (OR = 1.84 95% CI = (1.42, 2.40)), and high blood pressure (OR = 1.51 95% CI = (1.26, s1.82)). During 12 years of follow-up, we found evidence that hazard ratios for adiposity can be confounded by disease-related weight loss. Our findings raise the possibility that prebaseline weight loss can confound the estimation of risk due to adiposity at baseline in a cohort study.     

Preferential reductions in intermuscular and visceral adipose tissue with exercise-induced weight loss compared with calorie restriction

Intermuscular adipose tissue (IMAT) and visceral adipose tissue (VAT) are associated with insulin resistance. We sought to determine whether exercise-induced weight loss (EX) results in greater reductions in IMAT and VAT compared with similar weight loss induced by calorie restriction (CR) and whether these changes are associated with improvements in glucoregulation. Sedentary men and women (50-60 yr; body mass index of 23.5-29.9 kg/m(2)) were randomized to 1 yr of CR (n = 17), EX (n = 16), or a control group (CON; n = 6). Bilateral thigh IMAT and VAT volumes were quantified using multi-slice magnetic resonance imaging. Insulin sensitivity index (ISI) was determined from oral glucose tolerance test glucose and insulin levels. Weight loss was comparable (P = 0.25) in the CR (-10.8 ± 1.4%) and EX groups (-8.3 ± 1.5%) and greater than in the control group (-2.0 ± 2.4%; P < 0.05). IMAT and VAT reductions were larger in the CR and EX groups than in the CON group (P ≤ 0.05). After controlling for differences in total fat mass change between the CR and EX groups, IMAT and VAT reductions were nearly twofold greater (P ≤ 0.05) in the EX group than in the CR group (IMAT: -45 ±5 vs. -25 ± 5 ml; VAT: -490 ± 64 vs. -267 ± 61 ml). In the EX group, the reductions in IMAT were correlated with increases in ISI (r = -0.71; P = 0.003), whereas in the CR group, VAT reductions were correlated with increases in ISI (r = -0.64; P = 0.006). In conclusion, calorie restriction and exercise-induced weight loss both decrease IMAT and VAT volumes. However, exercise appears to result in preferential reductions in these fat depots.     

Mortality in young offenders: retrospective cohort study

Objectives To estimate overall and cause specific standardised mortality ratios in young offenders.Design Comparison of mortality data in cohort of young offenders.Settings State of Victoria, Australia.Subjects Cohort of young offenders aged 10-20 years with a first custodial sentence from 1 January 1988 to 31 December 1999.Main outcome measures Deaths ascertained by matching with the national death index, a database containing records of all deaths in Australia since 1980. Death rates in the reference Victorian population used to calculate standardised mortality ratios.Results The offender cohort comprised 2621 men and 228 women with 11 333 person years of observation. The median age of first detention was 17.9 years for men and 18.4 years for women. Median follow up was 3.3 years for men and 1.4 years for women. Overall standardised mortality ratio adjusted for age (expressed as a ratio) was 9.4 (95% confidence interval 7.4 to 11.9) for men and 41.3 (20.2 to 84.7) for women. Cause specific standardised mortality ratios for men were 25.7 (17.9 to 36.9) for drug related causes, 9.2 (5.8 to 15) for suicide, and 5.7 (3.6 to 9.2) for non-intentional injury. A quarter of drug related deaths in men aged 15-19 years were in offenders.Conclusions Social policies for young offenders should address both the prevalent drug and mental health problems as well the high levels of social disadvantage.     

Internal disinhibition predicts weight regain following weight loss and weight loss maintenance

Objective: The disinhibition scale of the Eating Inventory predicts weight loss outcome; however, it may include multiple factors. The purpose of this study was to examine the factor structure of the disinhibition scale and determine how its factors independently relate to long‐term weight loss outcomes. Research Methods and Procedures: Exploratory factor analysis of the disinhibition scale was conducted on 286 participants in a behavioral weight loss trial (TRIM), and confirmatory factor analysis was conducted on 3345 members of the National Weight Control Registry (NWCR), a registry of successful weight loss maintainers. Multivariate regressions were used to examine the relationships between the disinhibition scale factors and weight over time in both samples. Results: Using baseline data from TRIM, two factors were extracted from the disinhibition scale: 1) an “internal” factor that described eating in response to internal cues, such as feelings and thoughts; and 2) an “external” factor that described eating in response to external cues, such as social events. This factor structure was confirmed using confirmatory factor analysis in the NWCR. In TRIM, internal disinhibition significantly predicted weight loss at 6 months (p = 0.03) and marginally significantly predicted weight loss at 18 months (p = 0.06), with higher levels of internal disinhibition at baseline predicting less weight loss; external disinhibition did not predict weight loss at any time‐point. In NWCR, internal disinhibition significantly predicted one‐year weight change (p = 0.001), while external disinhibition did not. Discussion: These results suggest that it is the disinhibition of eating in response to internal cues that is associated with poorer long‐term weight loss outcomes.     

Impact of small body weight on tenofovir-associated renal dysfunction in HIV-infected patients: a retrospective cohort study of Japanese patients

Background

Treatment with tenofovir is sometimes associated with renal dysfunction. Limited information is available on this side effect in patients with small body weight, although the use of tenofovir will spread rapidly in Asia and Africa, where patients are likely to be of smaller body weight.

Methods

In a single-center cohort, Japanese patients with HIV infection who started tenofovir-containing antiretroviral therapy were retrospectively analyzed. The incidence of tenofovir-associated renal dysfunction, defined as more than 25% decrement of estimated glomerular filtration rate (eGFR) from the baseline, was determined. The effects of small body weight and body mass index (BMI) on tenofovir-associated renal dysfunction, respectively, were estimated in univariate and multivariate Cox hazards models as the primary exposure. Other possible risk factors were evaluated by univariate analysis and those found significant were entered into the multivariate analysis.

Results

The median weight of 495 patients was 63 kg. Tenofovir-related renal dysfunction occurred in 97 (19.6%) patients (incidence: 10.5 per 100 person-years). Univariate analysis showed that the incidence of tenofovir-related renal dysfunction was significantly associated with smaller body weight and BMI, respectively (per 5 kg decrement, HR = 1.23; 95% CI, 1.10–1.37; p<0.001)(per 1 kg/m² decrement, HR = 1.14; 95% CI, 1.05–1.23; p = 0.001). Old age, high baseline eGFR, low serum creatinine, low CD4 count, high HIV viral load, concurrent nephrotoxic drugs, hepatitis C infection, and current smoking were also associated with tenofovir-related renal dysfunction. Multivariate analysis identified small body weight as a significant risk (adjusted HR = 1.13; 95% CI, 1.01–1.27; p = 0.039), while small BMI had marginal significance (adjusted HR = 1.07; 95% CI 1.00–1.16; p = 0.058).

Conclusion

The incidence of tenofovir-associated renal dysfunction in Japanese patients was high. Small body weight was identified as an independent risk factor for tenofovir-associated renal dysfunction. Close monitoring of renal function is advocated for patients with small body weight treated with tenofovir.     

The effects of pre-pregnancy body mass index and gestational weight gain on perinatal outcomes in Korean women: a retrospective cohort study

Background  

The purpose of the study was to evaluate the effects of maternal pre-pregnancy body mass index (BMI) and gestational weight gain on perinatal outcomes in a population of Korean women.     

Long interpregnancy interval and adverse perinatal outcomes: A retrospective cohort study

We conducted a retrospective cohort study of 9,552 women experiencing their second delivery between 2014 and 2016 at the International Peace Maternity and Child Health Hospital to investigate the association between the interpregnancy interval(IPI)and adverse perinatal outcomes. With the 12–23-mon IPI as the reference category, logistic regression analyzes were used to examine associations between different IPIs(12, 12–23, 24–59, 60–119, and ≥120 mon) and perinatal outcomes(gestational diabetes mellitus, premature membrane rupture, gestational hypertension, preterm birth, low birth weight, and macrosomia).Compared with the 12–23-mon IPI category, women with longer IPIs had a higher risk of adverse perinatal outcomes, and those with an IPI ≥120 mon had the highest risk of gestational diabetes mellitus and premature membrane rupture(adjusted odds ratio(OR) 1.76, 95% confidence interval(CI) 1.32–2.35 and adjusted OR 2.03, 95% CI 1.53–2.67, respectively). These results indicate that a longer IPI is associated with a higher risk of adverse perinatal outcomes and an IPI of ≥120 mon appears to be independently associated with a higher risk of gestational diabetes mellitus and premature membrane rupture.     

Following 411 Cochrane protocols to completion: a retrospective cohort study

Background

Cochrane reviews are regarded as being scientifically rigorous and are increasingly used by a variety of stakeholders. However, factors predicting the publication of Cochrane reviews have never been reported. This is important because if a higher proportion of Cochrane protocols with certain characteristics (e.g., funding) are being published, this may lead to inaccurate decisions. We examined the frequency of published and unpublished Cochrane reviews and protocol factors that predict the publication of Cochrane reviews.

Methodology/Principal Findings

Retrospective cohort study of Cochrane protocols published in 2000 (Issues 2 to 4) and 2001 (Issue 1). The publication status of these reviews was followed up to Issue 1, 2008 in The Cochrane Library. Survival analysis of the time from protocol publication to the first review publication and protocol factors predicting the time to publication was conducted. There were 411 new Cochrane protocols in the cohort. After excluding 39; 71/372 (19.1%) were unpublished and 301/372 (80.9%) were published as full Cochrane reviews at the time of study analysis (January 2008). The median time to publication was 2.4 years (range: 0.15 to 8.96). Multivariate analyses revealed that shorter time to publication was associated with the review subsequently being updated (hazard ratio, HR: 1.80 [95% confidence interval, CI: 1.39 to 2.33 years]) and longer time to publication was associated with the review having two published protocols, indicating changes to the review plan (HR: 0.33 [95% CI: 0.12 to 0.90 years]).

Conclusions/Significance

Only about 80% Cochrane protocols were published as full reviews after over 8 years of follow-up. The median time to publication was 2.4 years and some reviews took much longer. Strategies to decrease time to publication should be considered, such as streamlining the review process, increased support for authors when protocol amendments occur, and better infrastructure for updating Cochrane reviews.     

Fate of biomedical research protocols and publication bias in France: retrospective cohort study

Objectives To describe the fate of protocols approved by the French research ethics committees, a national system created by the French 1988 Huriet-Sérusclat Act; to assess publication bias at a national level.Design Retrospective cohort study.Setting Representative sample of 25/48 French research ethics committees in 1994.Protocols 649 research protocols approved by committees, with follow-up information.Main outcome measures Protocols'' initial characteristics (design, study size, investigator) abstracted from committees'' archives; follow-up information (rates of initiation, completion, and publication) obtained from mailed questionnaire to principal investigators.Results Completed questionnaires were available for 649/976 (69%) protocols. Of these, 581 (90%) studies were initiated, 501/581 (86%) were completed, and 190/501 (38%) were published. Studies with confirmatory results were more likely to be published as scientific papers than were studies with inconclusive results (adjusted odds ratio 4.59, 95% confidence interval 2.21 to 9.54). Moreover, studies with confirmatory results were published more quickly than studies with inconclusive results (hazard ratio 2.48, 1.36 to 4.55).Conclusion At a national level, too many research studies are not completed, and among those completed too many are not published. We suggest capitalising on research ethics committees to register and follow all authorised research on human participants on a systematic and prospective basis.     

Atypical antipsychotic drugs and risk of ischaemic stroke: population based retrospective cohort study

Objective To compare the incidence of admissions to hospital for stroke among older adults with dementia receiving atypical or typical antipsychotics.Design Population based retrospective cohort study.Setting Ontario, Canada.Patients 32 710 older adults (≤ 65 years) with dementia (17 845 dispensed an atypical antipsychotic and 14 865 dispensed a typical antipsychotic).Main outcome measures Admission to hospital with the most responsible diagnosis (single most important condition responsible for the patient''s admission) of ischaemic stroke. Observation of patients until they were either admitted to hospital with ischaemic stroke, stopped taking antipsychotics, died, or the study ended.Results After adjustment for potential confounders, participants receiving atypical antipsychotics showed no significant increase in risk of ischaemic stroke compared with those receiving typical antipsychotics (adjusted hazard ratio 1.01, 95% confidence interval 0.81 to 1.26). This finding was consistent in a series of subgroup analyses, including ones of individual atypical antipsychotic drugs (risperidone, olanzapine, and quetiapine) and selected subpopulations of the main cohorts.Conclusion Older adults with dementia who take atypical antipsychotics have a similar risk of ischaemic stroke to those taking typical antipsychotics.     

Financial ties and concordance between results and conclusions in meta-analyses: retrospective cohort study

Objective To determine whether financial ties to one drug company are associated with favourable results or conclusions in meta-analyses on antihypertensive drugs.Design Retrospective cohort study.Setting Meta-analyses published up to December 2004 that were not duplicates and evaluated the effects of antihypertensive drugs compared with any comparator on clinical end points in adults. Financial ties were categorised as one drug company compared with all others.Main outcome measures The main outcomes were the results and conclusions of meta-analyses, with both outcomes separately categorised as being favourable or not favourable towards the study drug. We also collected data on characteristics of meta-analyses that the literature suggested might be associated with favourable results or conclusions.Results 124 meta-analyses were included in the study, 49 (40%) of which had financial ties to one drug company. On univariate logistic regression analyses, meta-analyses of better methodological quality were more likely to have favourable results (odds ratio 1.16, 95% confidence interval 1.07 to 1.27). Although financial ties to one drug company were not associated with favourable results, such ties constituted the only characteristic significantly associated with favourable conclusions (4.09, 1.30 to 12.83). When controlling for other characteristics of meta-analyses in multiple logistic regression analyses, meta-analyses that had financial ties to one drug company remained more likely to report favourable conclusions (5.11, 1.54 to 16.92).Conclusion Meta-analyses on antihypertensive drugs and with financial ties to one drug company are not associated with favourable results but are associated with favourable conclusions.