The antioxidant vitamins and cardiovascular disease. A critical review of epidemiologic and clinical trial data

PURPOSE

To review prospective epidemiologic studies and randomized trials regarding the role of antioxidant vitamins (vitamins E and C and beta-carotene) in the prevention of cardiovascular disease, with emphasis on differences in results obtained by these two types of studies.

DATA SOURCES

Computerized and manual searches of the literature on antioxidant vitamins and cardiovascular disease.

STUDY SELECTION

Prospective epidemiologic studies and randomized trials that included 100 or more participants and provided quantified estimates of antioxidant vitamin intake.

DATA SYNTHESIS

Comparisons of relative risk reductions (RRR) across observational studies and randomized trials, including assessment of dose-response relations.

RESULTS

All three large epidemiologic cohort studies of vitamin E noted that high-level vitamin E intake or supplementation was associated with a significant reduction in cardiovascular disease (RRR range, 31% to 65%), as measured by various fatal and nonfatal cardiovascular end points. To obtain these reductions, vitamin E supplementation must last at least 2 years. Less consistent reductions were seen in studies of beta-carotene (RRR range, -2% to 46%) and vitamin C (RRR range, -25% to 51%). Considerable biases in observational studies, such as different health behaviors of persons using antioxidants, may account for the observed benefit. By contrast, none of the completed randomized trials showed any clear reduction in cardiovascular disease with vitamin E, vitamin C, or beta-carotene supplementation. The trials were not specifically designed to assess cardiovascular disease, did not provide data on nonfatal cardiovascular end points, may have had insufficient treatment durations, and used suboptimal vitamin E doses. The completed trials were of adequate size to indicate that the true therapeutic benefit of vitamin E and other antioxidants in reducing fatal cardiovascular disease (a survival benefit as long as 5 years) is probably more modest than the epidemiologic data suggest.

CONCLUSION

The epidemiologic data suggest that antioxidant vitamins reduce cardiovascular disease, with the clearest effect for vitamin E; however, completed randomized trials do not support this finding. Much of this controversy should be resolved by the ongoing large-scale and long-term randomized trials designed specifically to evaluate effects on cardiovascular disease.

Characteristics and mortality outcomes of thrombolysis trial participants and nonparticipants: a population-based comparison

OBJECTIVES

This study was done to compare characteristics and outcomes of patients with acute myocardial infarction participating in two thrombolysis trials with those of nontrial patients at study hospitals and external hospitals.

BACKGROUND

Preferential recruitment of lower risk patients into randomized trials of thrombolysis has been suggested by earlier studies. However, to date there has not been a definitive population-based comparison of characteristics and outcomes for thrombolysis trial participants and nonparticipants.

METHODS

Population-based data on hospital admissions and mortality from acute myocardial infarction for all hospitals in Ontario from 1989 to 1992 were linked to data on trial participants in two distinct thrombolysis studies (GUSTO I and LATE). Included were 1,304 patients entered into GUSTO, 12,657 nonparticipants at GUSTO hospitals, 249 patients entered into LATE, 5,997 nonparticipants at LATE hospitals and 12,299 patients at external hospitals. The main outcomes were differences in age, gender, comorbidity scores, coronary revascularization and survival to hospital discharge.

RESULTS

Patients in both GUSTO and LATE were significantly more likely to be <70 years old (odds ratio [OR] 2.8 and 3.2, respectively), to be male (OR 2.0 and 2.1, respectively), to have low comorbidity scores (OR 2.0 and 2.3, respectively) and, for GUSTO alone, to undergo coronary revascularization (OR 2.4). Nontrial patients were similar between trial hospitals and external hospitals. In-hospital mortality rates for GUSTO and LATE patients were lower (6.9% and 6.6%, respectively) than for nonparticipants at study hospitals (16.8% and 19.7%, respectively; p<0.001 for both comparisons). Survival to hospital discharge remained higher among GUSTO (OR 1.9) and LATE patients (OR 2.0) than nonparticipants at study hospitals even after adjustment for age, gender, revascularization and comorbidity scores.

CONCLUSIONS

Compared with nontrial patients, thrombolysis trial participants are younger, more often male, undergo more revascularization and have less comorbid disease. Even after adjustment for these factors, participants have a survival advantage over nonparticipants that is larger than expected from thrombolysis alone. These findings are not attributable to inferior care or skewed populations at hospitals that did not join these major trials. Further study of these selection biases may guide future trial design and deepen our understanding of why thrombolytics have been underused for high risk patients in routine practice.

Risk factors for adenocarcinoma and squamous cell carcinoma of the cervix in women aged 20-44 years: the UK National Case-Control Study of Cervical Cancer

We report results on risk factors for invasive squamous cell and adenocarcinomas of the cervix in women aged 20–44 years from the UK National Case–Control Study of Cervical Cancer, including 180 women with adenocarcinoma, 391 women with squamous cell carcinoma and 923 population controls. The risk of both squamous cell and adenocarcinoma was strongly related to the lifetime number of sexual partners, and, independently, to age at first intercourse. The risk of both types of cervical cancer increased with increasing duration of use of oral contraceptives, and this effect was most marked in current and recent users of oral contraceptives. The risk of squamous cell carcinoma was associated with high parity and the risk of both squamous cell and adenocarcinoma increased with early age at first birth. Long duration smoking (20 or more years) was associated with a two-fold increase in the risk of squamous cell carcinoma, but smoking was not associated with the risk of adenocarcinoma. Further studies are needed to confirm the suggestion from this and other studies of differences in risk related to smoking between squamous cell and adenocarcinomas of the cervix.

Trends in maternal mortality in India over two decades in nationally representative surveys

OBJECTIVE

To assess national and regional trends and causes-specific distribution of maternal mortality in India.

DESIGN

Nationally representative cross-sectional surveys.

SETTING

All of India from 1997 to 2020.

SAMPLE

About 10 000 maternal deaths among 4.3 million live births over two decades.

METHODS

We analysed trends in the maternal mortality ratio (MMR) from 1997 through 2020, estimated absolute maternal deaths and examined the causes of maternal death using nationally representative data sources. We partitioned female deaths (aged 15-49 years) and live birth totals, based on the 2001-2014 Million Death Study to United Nations (UN) demographic totals for the country.

MAIN OUTCOME MEASURES

Maternal mortality burden and distribution of causes.

RESULTS

The MMR declined in India by about 70% from 398/100 000 live births (95% CI 378-417) in 1997-98 to 99/100 000 (90-108) in 2020. About 1.30 million (95% CI 1.26-1.35 million) maternal deaths occurred between 1997 and 2020, with about 23 800 (95% CI 21 700-26 000) in 2020, with most occurring in poorer states (63%) and among women aged 20-29 years (58%). The MMRs for Assam (215), Uttar Pradesh/Uttarakhand (192) and Madhya Pradesh/Chhattisgarh (170) were highest, surpassing India's 2016-2018 estimate of 113 (95% CI 103-123). After adjustment for education and other variables, the risks of maternal death were highest in rural and tribal areas of north-eastern and northern states. The leading causes of maternal death were obstetric haemorrhage (47%; higher in poorer states), pregnancy-related infection (12%) and hypertensive disorders of pregnancy (7%).

CONCLUSIONS

India could achieve the UN 2030 MMR goals if the average rate of reduction is maintained. However, without further intervention, the poorer states will not.

TWEETABLE ABSTRACT

We estimated that 1.3 million Indian women died from maternal causes over the last two decades. Although maternal mortality rates have fallen by 70% overall, the poorer states lag behind.

The cost-effectiveness of forty health interventions in Guinea

Addressing diseases of a high burden with the most cost-effective interventions could do much to reduce disease in the population. We conducted a cost-effectiveness analysis of 40 health interventions in Guinea, a low-income country in sub-Saharan Africa, using local data. Interventions were selected from treatment protocols at health centres, first referral hospitals and national programmes in Guinea, based upon consultation with health care providers and government plans. For each intervention, we calculated the costs (comprising labour, drugs, supplies, equipment, and overhead) in relation to years of life saved, discounted at 3%. The results show that the per capita costs and effectiveness of any intervention vary considerably. Average costs show no clear pattern by level of care, but effectiveness is generally highest for curative hospital interventions. Several interventions have a cost-effectiveness of US$100 per year of life saved (LYS) or less, and address more than 5% of total years of life lost. These include health centre interventions such as: treatment of childhood pneumonia ($3/LYS); rehydration therapy for diarrhoea ($7/LYS); integrated management of childhood pneumonia, malaria and diarrhoea ($8/LYS); short-course treatment of tuberculosis ($12/LYS); treatment of childhood malaria ($13/LYS), and childhood vaccination ($25/LYS). Outreach programmes for impregnated bed nets against malaria cost $43/LYS. Maternal and perinatal diseases, have slightly less cost-effective interventions: integrated family planning, prenatal and delivery care at health centres ($109/LYS) or outreach programmes to provide prenatal and delivery care ($283/LYS). A minimum package of health services would cost approximately $13 per capita, and would address a large proportion (69%) of major causes of premature mortality. This minimum package would cost about three times the current public spending on health, suggesting that health spending needs to rise to achieve good health outcomes.

The impact of cigarette smoking on life expectancy between 1980 and 2010: a global perspective

INTRODUCTION

Tobacco smoking is among the leading causes of preventable mortality worldwide. We assessed the impact of smoking on life expectancy worldwide between 1980 and 2010.

METHODS

We retrieved cause-specific mortality data from the WHO Mortality Database by sex, year and age for 63 countries with high or moderate quality data (1980-2010). Using the time of the peak of the smoking epidemic by country, relative risks from the three waves of the Cancer Prevention Study were applied to calculate the smoking impact ratio and population attributable fraction. Finally, we estimated the potential gain in life expectancy at age 40 if smoking-related deaths in middle age (40-79 years) were eliminated.

RESULTS

Currently, tobacco smoking is related to approximately 20% of total adult mortality in the countries in this study (24% in men and 12% in women). If smoking-related deaths were eliminated, adult life expectancy would increase on average by 2.4 years in men (0.1 in Uzbekistan to 4.8 years in Hungary) and 1 year in women (0.1 in Kyrgyzstan to 2.9 years in the USA). The proportion of smoking-related mortality among men has declined in most countries, but has increased in the most populous country in the world, that is, China from 4.6% to 7.3%. Increases in the impact of tobacco on life expectancy were observed among women in high-income countries.

CONCLUSIONS

Recent trends indicate a substantial rise in the population-level impact of tobacco smoking on life expectancy in women and in middle-income countries. High-quality local data are needed in most low-income countries.

Effect of cyclosporine on fertility in male rats

The effect of cyclosporine (CsA) on fertility has assumed greater importance with the increasing numbers of pediatric transplantations being performed all over the world. Conflicting reports on the effects of CsA on sex hormones are available. This experimental animal study was designed to examine the effect of CsA on testicular weight, sperm counts, seminiferous tubular diameter (STD), testicular morphology, DNA flowcytometry, sex hormone levels, and fertility in male rats. Those rats who received CsA (20 mg/kg per day) showed significant reductions in testicular weight (P < 0.05), sperm count (P < 0.01), Johnsen score (P < 0.05), STD (P < 0.01), serum testosterone levels (P < 0.05), haploid cell population (P < 0. 001) in the testis, and fertility (P < 0.001) compared to those receiving CsA 10 mg/kg per day and control rats. These findings will have an important bearing for children receiving cyclosporine for long periods to guide the physician in optimally adjusting long-term treatment.

Effect of continuous arteriovenous hemofiltration combined with systemic vasopressor therapy on depressed left ventricular contractility and tissue oxygen delivery in canine Escherichia coli sepsis

BACKGROUND

In a previous study, we showed that continuous arteriovenous hemofiltration (CAVH) reversed the depression in left ventricular (LV) contractility in canine Escherichia coli sepsis by the removal of a circulating substance the molecular weight of which is less than 30,000. Despite the normalization of LV contractility, however, we were unable to demonstrate an improvement in systemic arterial blood pressure (BP), presumably because the mechanisms underlying the depression in LV contractility and the decrease in BP are different in sepsis. In the current study, we examined the effect of combined treatment with CAVH and the alpha-adrenergic agonist phenylephrine on LV mechanics and tissue oxygen delivery in our canine E. coli model.

METHODS

Measurements were obtained at baseline (condition B), after 4 h of sepsis (condition S), and after 2 h of CAVH and phenylephrine (condition P) (total of 6 h of sepsis). During P, phenylephrine was infused to restore BP to that found at baseline. The slope of the end-systolic pressure-dimension relation was used as the index of LV contractility; LV anterior-posterior dimensions were measured by sonomicrometry.

RESULTS

During combined CAVH and phenylephrine treatment, the decrease in the slope of the end-systolic pressure-dimension relation otherwise observed at S was reversed. The slope (mean +/- SD) was 57.5 +/- 32 mmHg/mm at B versus 22.2 +/- 8 mmHg/mm at S (P < 0.05, B vs. S) versus 62 +/- 37 mmHg at P (P < 0.05 S vs. P) (analysis of variance). Mean BP was restored to that found at B (123 +/- 19 mmHg versus 82 +/- 14 mmHg (P < 0.05 B vs. S) versus 116 +/- 27 mmHg (P < 0.05 S vs. P). Combination treatment with CAVH and phenylephrine also improved stroke volume (39.3 +/- 13.5 versus 32 +/- 8 versus 44 +/- 12 ml) and tissue oxygen delivery during P compared with results obtained when phenylephrine was given alone.

CONCLUSIONS

Our study offers a rationale for the combined use of phenylephrine and CAVH in the reversal of cardiac depression and hypotension in sepsis.

Autism spectrum disorder and Klinefelter syndrome

BACKGROUND

Autism is a severe handicapping disorder of early childhood characterized by a distinct pattern of social and communication impairment with rigid ritualistic interests. In about 10-25% of cases, it is associated with known medical conditions. Population-based studies of autism have found that Klinefelter's syndrome (KS), a common chromosome abnormality, is sometimes associated with autism. However, few detailed case descriptions of patients with KS and autism have not been published.

CASE REPORT

In this paper, we describe the occurrence of autistic features in two cases of Klinefelter syndrome, one with the typical XXY karyotype and the other with the XXYY variant.

CONCLUSION

Autistic features may be more common in persons with Klinefelter syndrome than generally believed. We propose that all patients with KS should be screened for the presence of autism.

Smokeless tobacco use: a meta-analysis of risk and attributable mortality estimates for India

BACKGROUND

Use of smokeless tobacco (SLT) is widely prevalent in India and Indian subcontinent. Cohort and case-control studies in India and elsewhere report excess mortality due to its use.

OBJECTIVE

The aim was to estimate the SLT use-attributable deaths in males and females, aged 35 years and older, in India.

MATERIALS AND METHODS

Prevalence of SLT use in persons aged 35 years and older was obtained from the Global Adult Tobacco Survey in India and population size and deaths in the relevant age-sex groups were obtained from UN estimates (2010 revision) for 2008. A meta-relative risk (RR) based population attributable fraction was used to estimate attributable deaths in persons aged 35 years and older. A random effects model was used in the meta-analysis on all-cause mortality from SLT use in India including four cohort and one case-control study. The studies included in the meta-analysis were adjusted for smoking, age and education.

RESULTS

The prevalence of SLT use in India was 25.2% for men and 24.5% for women aged 35 years and older. RRs for females and males were 1.34 (1.27-1.42) and 1.17 (1.05-1.42), respectively. The number of deaths attributable to SLT use in India is estimated to be 368127 (217,076 women and 151,051 men), with nearly three-fifth (60%) of these deaths occurring among women.

CONCLUSION

SLT use caused over 350,000 deaths in India in 2010, and nearly three-fifth of SLT use-attributable deaths were among women in India. This calls for targeted public health intervention focusing on SLT products especially among women.

Optimal cut-off value of fecal calprotectin for the evaluation of ulcerative colitis: An unsolved issue?

Introduction

There is variability in the fecal calprotectin (FCP) cut‐off level for the prediction of ulcerative colitis (UC) disease activity and differentiation from irritable bowel disease (IBS‐D). The FCP cut‐off levels vary from country to country.

Aims

We aimed to assess FCP as a marker of disease activity in patients with UC. We determined the optimal FCP cut‐off value for differentiating UC and IBS‐D.

Methods

In a prospective study, we enrolled 76 UC and 30 IBS‐D patients. We studied the correlation of FCP with disease activity/extent as well as its role in differentiating UC from IBS‐D. We also reviewed literature regarding the optimal FCP cut‐off level for the prediction of disease activity and differentiation from IBS‐D patients.

Results

Sensitivity, specificity, positive predictive value, and negative predictive value of FCP (cut‐off level, 158 μg/g) for the prediction of complete mucosal healing (using Mayo endoscopic subscore) were 90, 85, 94.7, and 73.3%, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value of FCP (cut‐off level, 425 μg/g) for the prediction of inactive disease (Mayo Score ≤ 2) were 94.3, 88.7, 86.2, and 95.4%, respectively. We also found a FCP cut‐off value of 188 μg/g for the differentiation of UC from IBS‐D.

Conclusions

The study reveals the large quantitative differences in FCP cut‐off levels in different study populations. This study demonstrates a wide variation in FCP cut‐off levels in the initial diagnosis of UC as well as in follow‐up post‐treatment. Therefore, this test requires validation of the available test kits and finding of appropriate cut‐off levels for different study populations.

Depression of blast transformation of peripheral leukocytes by plasma from pregnant women

The blast transformation of peripheral leukocytes from pregnant and nonpregnant women has been studied at different time intervals with graded concentrations of phytohemagglutinin. The transformation is markedly depressed during pregnancy. Leukocytes from nonpregnant women and men show diminished transformation when cultured in a medium containing plasma from pregnant women.

In vitro sperm phagocytosis by human peritoneal macrophages in endometriosis-associated infertility

PROBLEM

The mechanism of infertility in women with endometriosis remains obscure. In this context the role of peritoneal macrophage's sperm phagocytic ability in infertile women with and without endometriosis was investigated.

METHOD

Analysis of peritoneal macrophage concentration and in vitro sperm phagocytosis in 10 infertile women with endometriosis and 10 infertile women without endometriosis was carried out.

RESULTS

It was observed that infertile women with endometriosis are associated with higher concentration and higher sperm phagocytic activity of peritoneal macrophages than those without endometriosis.

CONCLUSION

Despite the small number of women in this study, it may be concluded that the increased number of peritoneal macrophages coupled with enhanced in vitro sperm phagocytosis may disturb fertilization and thereby cause infertility.

Bidi and cigarette smoking and risk of acute myocardial infarction among males in urban India

Death from myocardial infarction (MI) in India is exacerbated by smoking of bidis or cigarettes. Smoking among 309 men with incident MI was compared to 618 age matched controls; 56% of the individuals with MI and 26% of controls were current smokers. Current smokers had a relative risk of 4.7 (95% confidence interval (CI) 3.2 to 6.9) compared to never smokers. Relative risks for smoking more than 10 cigarettes or 10 bidis daily were 9.1 (95% CI 4.7 to 17.7) and 8.1 (95% CI 4.3 to 15.3), respectively. It is estimated that smoking may cause 53% (95% CI 47% to 64%) of MIs among urban males in India.