Effects of cigarette smoking on fasting triglyceride, total cholesterol, and HDL-cholesterol in women

Epigenetic age acceleration is associated with blood lipid levels in a multi-ancestry sample of older U.S. adults

Background

Dyslipidemia, which is characterized by an unfavorable lipid profile, is a key risk factor for cardiovascular disease (CVD). Understanding the relationships between epigenetic aging and lipid levels may help guide early prevention and treatment efforts for dyslipidemia.

Methods

We used weighted linear regression to cross-sectionally investigate the associations between five measures of epigenetic age acceleration estimated from whole blood DNA methylation (HorvathAge Acceleration, HannumAge Acceleration, PhenoAge Acceleration, GrimAge Acceleration, and DunedinPACE) and four blood lipid measures (total cholesterol (TC), LDL-C, HDL-C, and triglycerides (TG)) in 3,813 participants (mean age = 70 years) from the Health and Retirement Study (HRS). As a sensitivity analysis, we examined the same associations in participants who fasted prior to the blood draw (n = and f) and in participants who did not take lipid-lowering medication (n = 1,869). Using interaction models, we also examined whether the relationships between epigenetic age acceleration and blood lipids differ by demographic factors including age, sex, and educational attainment.

Results

After adjusting for age, race/ethnicity, sex, fasting status, and lipid-lowering medication use, greater epigenetic age acceleration was associated with lower TC, HDL-C, and LDL-C, and higher TG (p < 0.05). GrimAge acceleration and DunedinPACE associations with all lipids remained significant after further adjusting for body mass index, smoking status, and educational attainment. These associations were stronger in participants who fasted and who did not use lipid-lowering medication, particularly for LDL-C. We observed the largest number of interactions between DunedinPACE and demographic factors, where the associations with lipids were stronger in younger participants, females, and those with higher educational attainment.

Conclusion

Epigenetic age acceleration, a powerful biomarker of cellular aging, is highly associated with blood lipid levels in older adults. A greater understanding of how these associations differ across demographic groups can help shed light on the relationships between aging and downstream cardiovascular diseases. The inverse associations between epigenetic age and TC and LDL-C could be due to sample limitations or the non-linear relationship between age and these lipids, as both TC and LDL-C decrease faster at older ages. More studies are needed to further understand the temporal relationships between epigenetic age acceleration on blood lipids and other health outcomes.

The effects of maternal cigarette smoking on cadmium and lead levels, miRNA expression and biochemical parameters across the feto-placental unit

Several miRNAs have been previously identified to be associated with cigarette smoke and/or the toxic metals cadmium (Cd) and lead (Pb). The aim of this study was to investigate the associations of maternal cigarette smoking with cadmium (Cd) and lead (Pb) levels, candidate miRNA expression and biochemical parameters across the feto-placental unit. miRNAs were isolated according to protocols provided by manufacturer from 72 healthy postpartum women using Qiagens' kits based on phenol/guanidine samples lysis and silica-membrane purification of total RNA. Candidate miRNAs (miR-1537, miR-190b, miR-16, miR-21, and miR-146a) were quantified by real-time PCR. Biochemical parameters were analyzed in plasma samples by standardized and harmonized enzymatic methods using appropriate calibrators, while CRP was determined by immunoturbidimetric method. Concentration of Cd and Pb in whole blood and placenta samples were measured by inductively coupled plasma mass spectroscopy. Cd levels in smokers were higher in all of the analyzed compartments of the feto-placental unit, Pb in maternal blood and placenta than non-smokers. Smokers also had a higher expression of miR-16 in maternal and miR-146a in cord plasma, and lower expression of miR-21 in the placenta in comparison to non-smokers. Urate concentrations in the maternal plasma of smokers were lower than this value in non-smokers. The study has demonstrated that maternal smoking was associated with toxic metals (Cd and Pb) levels, urate concentration and alteration of miRNA expression. Given that the effects of maternal smoking on miRNA expression are inadequate, all compartments of the feto-placental unit should be analyzed to obtain a complete picture. This paper is the first to report on the results of expression of cellular and circulating miRNAs simultaneously in maternal and fetal compartments and in the placenta.

Fasting, non-fasting and postprandial triglycerides for screening cardiometabolic risk

Fasting triacylglycerols have long been associated with cardiovascular disease (CVD) and other cardiometabolic conditions. Evidence suggests that non-fasting triglycerides (i.e. measured within 8 h of eating) better predict CVD than fasting triglycerides, which has led several organisations to recommend non-fasting lipid panels as the new clinical standard. However, unstandardised assessment protocols associated with non-fasting triglyceride measurement may lead to misclassification, with at-risk individuals being overlooked. A third type of triglyceride assessment, postprandial testing, is more controlled, yet historically has been difficult to implement due to the time and effort required to execute it. Here, we review differences in assessment, the underlying physiology and the pathophysiological relevance of elevated fasting, non-fasting and postprandial triglycerides. We also present data suggesting that there may be a distinct advantage of postprandial triglycerides, even over non-fasting triglycerides, for early detection of CVD risk and offer suggestions to make postprandial protocols more clinically feasible.

Adherence to a Healthy Lifestyle and the Risk of All-Cause Mortality and Cardiovascular Events in Individuals With Diabetes: The ARIC Study

Objective: The relationship between combined healthy lifestyle and cardiovascular (CV) events in diabetes is unclear. We aim to investigate the association between a healthy lifestyle score (HLS) and the risk of mortality and CV events in diabetes.

Methods: We examined the associations of six lifestyle factors scores (including healthy diet, moderate alcohol and regular coffee intakes, never smoking, physical activity, and normal weight) with diabetes in the Atherosclerosis Risk in Communities (ARIC) study of 3,804 participants with diabetes from the United States at baseline. Primary outcomes included all-cause mortality, CV mortality, and composite CV events (heart failure hospitalizations, myocardial infarction, fatal coronary heart disease, and stroke).

Results: Among these diabetic participants, 1,881 (49.4%), 683 (18.0%), and 1,600 (42.0%) cases of all-cause mortality, CV mortality, and CV events were documented, respectively, during the 26 years of follow-up. Further, the prevalence of these adverse events became lower with the increase of HLS (all P < 0.001). In the risk-factors adjusted Cox regression model, compared to participants with HLS of 0, participants with HLS of 2 had significant lower risk of all-cause mortality (HR = 0.811, 95% CI: 0.687–0.957, P = 0.013), CV mortality (HR = 0.744, 95% CI: 0.576–0.962, P = 0.024), and CV events (HR = 0.789, 95% CI: 0.661–0.943, P = 0.009). The association of HLS with CV events was stronger for women than men (P for interaction <0.05).

Conclusion: Adherence to a healthy lifestyle was associated with a lower risk of CV events and mortality in diabetics. Our findings suggest that the promotion of a healthy lifestyle would help reduce the increasing healthcare burden of diabetes.

Clinical Trial Registration:https://clinicaltrials.gov, Identifier: NCT00005131.

Association between triglycerides, known risk SNVs and conserved rare variation in SLC25A40 in a multi-ancestry cohort

BACKGROUND

Elevated triglycerides (TG) are associated with, and may be causal for, cardiovascular disease (CVD), and co-morbidities such as type II diabetes and metabolic syndrome. Pathogenic variants in APOA5 and APOC3 as well as risk SNVs in other genes [APOE (rs429358, rs7412), APOA1/C3/A4/A5 gene cluster (rs964184), INSR (rs7248104), CETP (rs7205804), GCKR (rs1260326)] have been shown to affect TG levels. Knowledge of genetic causes for elevated TG may lead to early intervention and targeted treatment for CVD. We previously identified linkage and association of a rare, highly conserved missense variant in SLC25A40, rs762174003, with hypertriglyceridemia (HTG) in a single large family, and replicated this association with rare, highly conserved missense variants in a European American and African American sample.

METHODS

Here, we analyzed a longitudinal mixed-ancestry cohort (European, African and Asian ancestry, N = 8966) from the Electronic Medical Record and Genomics (eMERGE) Network. We tested associations between median TG and the genes of interest, using linear regression, adjusting for sex, median age, median BMI, and the first two principal components of ancestry.

RESULTS

We replicated the association between TG and APOC3, APOA5, and risk variation at APOE, APOA1/C3/A4/A5 gene cluster, and GCKR. We failed to replicate the association between rare, highly conserved variation at SLC25A40 and TG, as well as for risk variation at INSR and CETP.

CONCLUSIONS

Analysis using data from electronic health records presents challenges that need to be overcome. Although large amounts of genotype data is becoming increasingly accessible, usable phenotype data can be challenging to obtain. We were able to replicate known, strong associations, but were unable to replicate moderate associations due to the limited sample size and missing drug information.

A healthy lifestyle pattern and the risk of symptomatic gallstone disease: results from 2 prospective cohort studies

BACKGROUND

Symptomatic gallstones cause high financial and disease burden for public health systems. The combined role of diet and other lifestyle factors has not been studied so far.

OBJECTIVES

We aimed to investigate the association between an a priori defined healthy lifestyle score (HLS, including healthy diet, moderate alcohol and regular coffee intakes, never smoking, physical activity, and normal weight) and the risk of symptomatic gallstone disease, and to estimate the proportion of cases potentially preventable by lifestyle modification.

METHODS

We followed 60,768 women from the Nurses' Health Study (NHS) and 40,744 men from the Health Professionals Follow-up Study (HPFS), both ongoing prospective cohort studies, from baseline (1986) until 2012. Symptomatic gallstone disease was self-reported and validated by review of medical records. The association between the HLS and the risk of symptomatic gallstone disease was investigated using Cox proportional hazards regression.

RESULTS

During 1,156,079 and 769,287 person-years of follow-up, respectively, 6946 women and 2513 men reported symptomatic gallstone disease. Comparing 6 with 0 points of the HLS, the multivariable HR of symptomatic gallstone disease was 0.26 (95% CI: 0.15, 0.45) for women, and 0.17 (95% CI: 0.07, 0.43) for men. For individual lifestyle factors, multivariable and mutually adjusted partial population attributable risks (women and men) were 33% and 23% for BMI <25 kg/m2, 10% and 18% for ≥2 cups of coffee per day, 13% and 7% for moderate alcohol intake, 8% and 11% for a high Alternate Healthy Eating Index 2010, 9% and 5% for being physically active, and 1% and 5% for never smoking. The full population attributable risk percentage for all factors combined was 62% and 74%, respectively.

CONCLUSIONS

Findings from these large prospective studies indicate that adopting a healthy lifestyle, especially maintaining a healthy weight, can help to prevent a considerable proportion of symptomatic gallstone diseases.

Association of insulin resistance, from mid-life to late-life, with aortic stiffness in late-life: the Atherosclerosis Risk in Communities Study

Background

Insulin resistance may contribute to aortic stiffening that leads to end-organ damage. We examined the cross-sectional association and prospective association of insulin resistance and aortic stiffness in older adults without diabetes.

Methods

We analyzed 2571 men and women at Visit 5 (in 2011–2013), and 2350 men and women at repeat examinations from baseline at Visit 1 (in 1987–1989) to Visit 5 (in 2011–2013). Linear regression was used to estimate the difference in aortic stiffness per standard unit of HOMA-IR, TG/HDL-C, and TyG at Visit 5. Linear mixed effects were used to assess if high, as opposed to non-high, aortic stiffness (> 75th percentile) was preceded by a faster annual rate of change in log-HOMA-IR, log-TG/HDL-C, and log-TyG from Visit 1 to Visit 5.

Results

The mean age of participants was 75 years, 37% (n = 957) were men, and 17% (n = 433) were African American. At Visit 5, higher HOMA-IR, higher TG/HDL-C, and higher TyG were associated with higher aortic stiffness (16 cm/s per SD (95% CI 6, 27), 29 cm/s per SD (95% CI 18, 40), and 32 cm/s per SD (95% CI 22, 42), respectively). From Visit 1 to Visit 5, high aortic stiffness, compared to non-high aortic stiffness, was not preceded by a faster annual rate of change in log-HOMA-IR from baseline to 9 years (0.030 (95% CI 0.024, 0.035) vs. 0.025 (95% CI 0.021, 0.028); p = 0.15) or 9 years onward (0.011 (95% CI 0.007, 0.015) vs. 0.011 (95% CI 0.009, 0.013); p = 0.31); in log-TG/HDL-C from baseline to 9 years (0.019 (95% CI 0.015, 0.024) vs. 0.024 (95% CI 0.022, 0.026); p = 0.06) or 9 years onward (− 0.007 (95% CI − 0.010, − 0.005) vs. − 0.009 (95% CI − 0.010, − 0.007); p = 0.08); or in log-TyG from baseline to 9 years (0.002 (95% CI 0.002, 0.003) vs. 0.003 (95% CI 0.003, 0.003); p = 0.03) or 9 years onward (0 (95% CI 0, 0) vs. 0 (95% CI 0, 0); p = 0.08).

Conclusions

Among older adults without diabetes, insulin resistance was associated with aortic stiffness, but the putative role of insulin resistance in aortic stiffness over the life course requires further study.

The Influence of Sex on Cardiac Physiology and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death world-wide. Most of treatment strategies were based on studies conducted on male patients. Studies have shown that significant differences exist between the two sexes in the development of CVD. There are certain differences between men and women in the structure and physiological functions of the heart such as left ventricular mass index, resting heart rate, and contractile function. Accordingly, the pathological features of the heart such as the extend of hypertrophy, fibrosis, and remodeling are also different. In addition, different genders also affect clinical symptoms, responses to treatment and prognosis in the development of CVD. Therefore, it is important to take these differences into consideration when design treatment options for men and women.

Influence of cigarette smoking on hormone and lipid metabolism in women in late reproductive stage

BACKGROUND

The aim of the study was to analyze lipid and hormone metabolism, body mass index (BMI), and age parameters in late reproductive stage women in relation to cigarette smoking.

METHODS

The study enrolled 345 healthy late reproductive stage women living in Poland; 13.33% were smokers. The first part of the study assessed lipid metabolism (total cholesterol, high-density lipoprotein [HDL], low-density lipoprotein [LDL], and triglycerides) and hormone metabolism (estradiol [E2], follicle-stimulating hormone [FSH], and anti-Müllerian hormone [AMH] levels) in women in the early phase of the follicular menstrual cycle. The second part of study was carried out using the diagnostic survey method, with a standardized questionnaire (Primary Care Evaluation of Mental Disorders [PRIME-MD]) and the authors' own research tools.

RESULTS

The women were aged 42.3±4.5 years (mean ± SD). The BMI (24.8±4.04 kg/m2) did not differ significantly between the groups. The women who smoked cigarettes had a statistically significantly (p<0.05) lower level of HDL as well as higher LDL and triglyceride levels (p<0.05). Differences were also shown in hormone levels: non-smoking participants had statistically significantly higher levels of E2 and FSH (p<0.05). In the group of non-smoking women, age was a predictor exerting a significant positive impact on the levels of total cholesterol, LDL, triglycerides, and AMH (p<0.05). BMI contributed to a decline in HDL and triglyceride levels. In the group of smoking women, age significantly positively influenced the level of E2, and negatively influenced AMH. BMI was associated with a significant decrease in the HDL level.

CONCLUSION

Smoking cigarettes affects the physical health of women in late reproductive stage through negative influences on lipid and hormone metabolism, among other factors. Age is an unmodifiable factor adversely affecting both lipids and hormones. Higher BMI has a negative influence on lipid metabolism in both groups of women in this study.

Association between self-reported sleep duration and serum lipid profile in a middle-aged and elderly population in Taiwan: a community-based, cross-sectional study

OBJECTIVES

The association between sleep duration and serum lipid profile in the middle-aged and the elderly is unclear. The aim of this study was to investigate and evaluate the relationships between sleep duration and levels of serum total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C) and triglycerides in these populations.

DESIGN

Cross-sectional observational study.

SETTING

Community-based investigation in Guishan Township of northern Taiwan.

PARTICIPANTS

A total of 400 community-dwelling middle-aged and elderly individuals were enrolled. All participants underwent a baseline assessment in 2014, which included anthropometrics, blood samples and self-administered questionnaires. Participants were classified into three groups based on their sleep duration.

OUTCOME MEASURES

Multivariate logistic regression was used to obtain ORs and 95% CIs to assess the relationship between sleep duration and lipid profiles.

RESULTS

Participant mean age was 64.5 years and 35.3% were men. Subjects with longer (>7 hours) and shorter (<6 hours) nightly sleep duration had a higher prevalence of low HDL-C levels (HDL <40 mg/dL) than those with moderate sleep duration (6-7 hours). Multivariate logistic regression revealed that, compared with individuals with sleep duration of 6-7 hours, the ORs of having low HDL-C were 3.68 (95% CI 1.59 to 8.49) greater for individuals with sleep duration of <6 hours and 2.89 (95% CI 1.10 to 7.61) greater for individuals with sleep duration of >7 hours.

CONCLUSIONS

There was a U-shaped relationship between sleep duration and HDL-C levels. Sleep duration >7 hours or <6 hours increased the risk of low serum HDL-C levels.

Genome-wide association study of alcohol consumption and genetic overlap with other health-related traits in UK Biobank (N=112 117)

Alcohol consumption has been linked to over 200 diseases and is responsible for over 5% of the global disease burden. Well-known genetic variants in alcohol metabolizing genes, for example, ALDH2 and ADH1B, are strongly associated with alcohol consumption but have limited impact in European populations where they are found at low frequency. We performed a genome-wide association study (GWAS) of self-reported alcohol consumption in 112 117 individuals in the UK Biobank (UKB) sample of white British individuals. We report significant genome-wide associations at 14 loci. These include single-nucleotide polymorphisms (SNPs) in alcohol metabolizing genes (ADH1B/ADH1C/ADH5) and two loci in KLB, a gene recently associated with alcohol consumption. We also identify SNPs at novel loci including GCKR, CADM2 and FAM69C. Gene-based analyses found significant associations with genes implicated in the neurobiology of substance use (DRD2, PDE4B). GCTA analyses found a significant SNP-based heritability of self-reported alcohol consumption of 13% (se=0.01). Sex-specific analyses found largely overlapping GWAS loci and the genetic correlation (rG) between male and female alcohol consumption was 0.90 (s.e.=0.09, P-value=7.16 × 10^-23). Using LD score regression, genetic overlap was found between alcohol consumption and years of schooling (rG=0.18, s.e.=0.03), high-density lipoprotein cholesterol (rG=0.28, s.e.=0.05), smoking (rG=0.40, s.e.=0.06) and various anthropometric traits (for example, overweight, rG=-0.19, s.e.=0.05). This study replicates the association between alcohol consumption and alcohol metabolizing genes and KLB, and identifies novel gene associations that should be the focus of future studies investigating the neurobiology of alcohol consumption.

Association between the Time of Length since Smoking Cessation and Insulin Resistance in Asymptomatic Korean Male Ex-Smokers

AIM

Smoking is a major risk factor for diabetes mellitus, mainly due to decreased insulin secretion and increased insulin resistance. However, there has been little research on the effects of smoking cessation period on changes in insulin resistance. In this study, we investigated the relationships between the length of time since smoking cessation period and insulin resistance in asymptomatic Korean male ex-smokers.

METHODS

A total of 851 male adults were included in this study. We considered several factors that can affect insulin resistance, and through multiple linear regression analysis, we assessed the effect the length of time since smoking cessation on insulin resistance in ex-smokers. Insulin resistance was represented as the insulin resistance index estimated by homeostasis model assessment.

RESULTS

HOMA-IR values showed a statistically significant negative correlation with the length of time since smoking cessation (p = 0.009) in ex-smokers. After performing multiple linear regression analysis using factors that could potentially influence insulin resistance, we found that waist circumference (p = 0.026) and the length of time since smoking cessation (p = 0.039) were independent predictors of HOMA-IR in asymptomatic male ex-smokers.

CONCLUSION

The longer the smoking cessation period, the more the insulin resistance tended to decrease in asymptomatic Korean male ex-smokers.

The harms of smoking and benefits of smoking cessation in women compared with men with type 2 diabetes: an observational analysis of the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron modified release Controlled Evaluation) trial

OBJECTIVES

In general populations, the adverse effects of smoking on coronary risk have been demonstrated to be greater in women than in men; whether this is true for individuals with diabetes is unclear.

DESIGN

Cohort study.

SETTING

20 countries worldwide participating in the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron modified release Controlled Evaluation) trial.

PARTICIPANTS

11,140 patients with type 2 diabetes aged ≥ 55 years and in cardiovascular risk at the time of randomisation.

PRIMARY AND SECONDARY OUTCOME MEASURES

Major cardiovascular events (death from cardiovascular disease, non-fatal stroke or non-fatal myocardial infarction (MI)), all cardiovascular events (major cardiovascular event or peripheral arterial disease or transient ischaemic attack), and all-cause mortality. Secondary outcome measures were major coronary events (fatal and non-fatal MI), major cerebrovascular events (fatal and non-fatal stroke), nephropathy (new or worsening renal disease), and all cancer.

RESULTS

At baseline, 6466 (56% women) participants were never-smokers, 1550 (28% women) were daily smokers and 3124 (21% women) were former smokers. Median follow-up time was 5 years. In Cox regression models after multiple adjustments, compared with never smoking, daily smoking was associated with increased risk of all primary and secondary outcomes with the exception of major cerebrovascular disease. Only for major coronary events was there any evidence of a stronger effect in women than in men (ratio of the adjusted HRs women:men; 1.64 (0.83 to 3.26) p=0.08). For all other outcomes considered, the hazards of smoking were similar in men and women. Quitting smoking was associated with a 30% reduction in all-cause mortality (p=0.001) in both sexes.

CONCLUSIONS

In individuals with diabetes, the effects of smoking on all major forms of cardiovascular disease are equally as hazardous in women and men with the possible exception of major coronary events where there was some evidence of a greater hazard in women.

TRIAL REGISTRATION NUMBER

NCT00145925.

Adiposity throughout adulthood and risk of sudden cardiac death in women

BACKGROUND

Sudden cardiac death (SCD) is often the first manifestation of coronary heart disease (CHD) among women. Data regarding BMI and risk of SCD are limited and conflicting.

OBJECTIVES

We examined the association of BMI repeatedly measured over 32 years and BMI during early and mid-adulthood with risk of SCD in the Nurses' Health Study.

METHODS

We prospectively followed 72,484 women free of chronic disease from 1980-2012. We ascertained adult height, current weight, and weight at age 18 at baseline and updated weight biennially. The primary endpoint was SCD (n=445).

RESULTS

When updated biennially, higher BMI was associated with greater SCD risk after adjusting for confounders (p, linear trend: <0.001). Compared to a BMI of 21.0-22.9, the multivariate RR (95%CI) of SCD was 1.46 (1.05, 2.04) for BMI 25.0-29.9, 1.46 (1.00, 2.13) for BMI 30.0-34.9 and 2.18 (1.44, 3.28) for BMI ≥35.0. Among women with a BMI ≥35.0, SCD remained elevated even after adjustment for interim development of CHD and other mediators (RR: 1.72; 95%CI: 1.13, 2.60). In contrast, the association between BMI and fatal CHD risk was completely attenuated after adjustment for mediators. The magnitude of the association between BMI and SCD was greater when BMI was assessed at baseline or at age 18, at which time SCD risk remained significantly elevated at BMI≥30 after adjustment for mediators.

CONCLUSIONS

Higher BMI was associated with greater risk of SCD, particularly when assessed earlier in adulthood. Strategies to maintain a healthy weight throughout adulthood may minimize SCD incidence.

Factors influencing insulin resistance in relation to atherogenicity in mood disorders, the metabolic syndrome and tobacco use disorder

OBJECTIVE

This study examines the effects of malondialdehyde (MDA) and uric acid on insulin resistance and atherogenicity in subjects with and without mood disorders, the metabolic syndrome (MetS) and tobacco use disorder (TUD).

METHODS

We included 314 subjects with depression and bipolar depression, with and without the MetS and TUD and computed insulin resistance using the updated homeostasis model assessment (HOMA2IR) and atherogenicity using the atherogenic index of plasma (AIP), that is log10 (triglycerides/high density lipoprotein (HDL) cholesterol.

RESULTS

HOMA2IR is correlated with body mass index (BMI) and uric acid levels, but not with mood disorders and TUD, while the AIP is positively associated with BMI, mood disorders, TUD, uric acid, MDA and male sex. Uric acid is positively associated with insulin and triglycerides and negatively with HDL cholesterol. MDA is positively associated with triglyceride levels. Comorbid mood disorders and TUD further increase AIP but not insulin resistance. Glucose is positively associated with increasing age, male gender and BMI.

DISCUSSION

The results show that mood disorders, TUD and BMI together with elevated levels of uric acid and MDA independently contribute to increased atherogenic potential, while BMI and uric acid are risk factors for insulin resistance. The findings show that mood disorders and TUD are closely related to an increased atherogenic potential but not to insulin resistance or the MetS. Increased uric acid is a highly significant risk factor for insulin resistance and increased atherogenic potential. MDA, a marker of lipid peroxidation, further contributes to different aspects of the atherogenic potential. Mood disorders and TUD increase triglyceride levels, lower HDL cholesterol and are strongly associated with the atherogenic, but not insulin resistance, component of the MetS.

The relationship between serum brain-derived neurotrophic factor (BDNF) and cardiometabolic indices in schizophrenia

Brain derived neurotrophic factor (BDNF), which has been implicated in the pathogenesis of schizophrenia, has been recently shown to be involved in the regulation of metabolism and energy homeostasis. This study seeks to examine the relationship between BDNF, metabolic indices and cardiovascular (CVD) risk in patients with schizophrenia. Medical histories, demographic information and anthropometric measurements were collected and analyzed from 61 participants with schizophrenia. Fasting glucose and lipids were measured in a central laboratory, and serum BDNF was analyzed using commercially available enzyme-linked immunosorbent assay (ELISA). The 10-year CVD risk for each participant was computed using the Framingham risk score (FRS). Linear regressions were performed to examine the relationships between serum BDNF with body mass index (BMI), blood pressure (BP), triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C) and glucose. To examine the relationship between serum BDNF and FRS, serum BDNF was categorized into quartiles, and a multiple regression was performed. After adjusting for age, gender and current smoking status, diastolic BP (dBP) (p=0.045) and TG (p=0.015) were found to be significantly associated with serum BDNF. Participants in the highest quartile of serum BDNF had a 3.3 times increase in FRS over those in the lowest quartile. Our findings support the possible regulatory role of BDNF in metabolism and cardiovascular homeostasis among patients with schizophrenia similar to that observed among the non-mentally ill. Serum BDNF not only present itself as a candidate biomarker of schizophrenia but also might be a viable marker of metabolic co-morbidities associated with schizophrenia.

Triglycerides as a biological marker of repeated re-hospitalization resulting from deliberate self-harm in acute psychiatry patients: a prospective observational study

BACKGROUND

Biological factors have been associated with deliberate self-harm (DSH) but have not been integrated with clinical factors in routine risk assessments.This study aimed to examine the incremental validity of lipid levels and platelet serotonin when combined with psychosocial factors in risk assessments for repeated admissions due to DSH.

METHODS

In this prospective observational study of 196 acutely admitted patients, results of blood tests performed upon admission and the MINI Suicidal Scale and psychosocial DSH risk factor assessments performed at discharge were compared with the incidence of DSH recorded during the first 3 and 12 months after discharge.

RESULTS

High triglyceride levels were found to be a significant marker for patients admitted 3 or more times due to DSH (repeated DSH, DSH-R) when tested against other significant risk factors. When all (9) significant univariate factors associated with 12-month post-discharge DSH-R were analyzed in a multivariate logistic regression, the MINI Suicidal Scale (p = 0.043), a lack of insight (p = 0.040), and triglyceride level (p = 0.020) remained significant. The estimated 12-month area under the curve of the receiver operator characteristic (ROC-AUC) for DSH-R was 0.74 for triglycerides, 0.81 for the MINI, 0.89 for the MINI + psychosocial factors, and 0.91 for the MINI + psychosocial factors + triglycerides. The applied multifaceted approach also significantly discriminated between 12-month post-discharge DSH-R patients and other DSH patients, and a lack of insight (p = 0.047) and triglycerides (p = 0.046) remained significant for DSH-R patients in a multivariate analysis in which other DSH patients served as the reference group (rather than non-DSH patients).

CONCLUSION

The triglyceride values provided incremental validity to the MINI Suicidal Scale and psychosocial risk factors in the assessment of the risk of repeated DSH. Therefore, a bio-psychosocial approach appears promising, but further research is necessary to refine and validate this method.

Smoking as a risk factor for stroke in women compared with men: a systematic review and meta-analysis of 81 cohorts, including 3,980,359 individuals and 42,401 strokes

BACKGROUND AND PURPOSE

It is currently unknown whether the excess risk of stroke by smoking is the same for women and men. We performed a systematic review and meta-analysis to estimate the effect of smoking on stroke in women compared with men.

METHODS

PubMed MEDLINE was systematically searched for prospective population-based cohort studies published between January 1, 1966, and January 26, 2013. Studies that presented sex-specific estimates of the relative risk of stroke comparing current smoking with nonsmoking and its associated variability were selected. The sex-specific relative risks and their ratio (RRR), comparing women with men, were pooled using random-effects meta-analysis with inverse variance weighting. Similarly, the RRR for former versus never smoking was pooled.

RESULTS

Data from 81 prospective cohort studies that included 3,980,359 individuals and 42,401 strokes were available. Smoking was an independent risk factor for stroke in both sexes. Overall, the pooled multiple-adjusted RRR indicated a similar risk of stroke associated with smoking in women compared with men (RRR, 1.06 [95% confidence interval, 0.99-1.13]). In a regional analysis, there was evidence of a more harmful effect of smoking in women than in men in Western (RRR, 1.10 [1.02-1.18)] but not in Asian (RRR, 0.97 [0.87-1.09]) populations. Compared with never-smokers, the beneficial effects of quitting smoking among former smokers on stroke risk were similar between the sexes (RRR, 1.10 [0.99-1.22]).

CONCLUSIONS

Compared with nonsmokers, the excess risk of stroke is at least as great among women who smoke compared with men who smoke.

A prospective study of prepregnancy dietary fat intake and risk of gestational diabetes

BACKGROUND

Fatty acids play a vital role in glucose homeostasis; however, studies on habitual dietary fat intakes and gestational diabetes mellitus (GDM) risk are limited and provide conflicting findings.

OBJECTIVE

We determined whether the total amount and the type and source of prepregnancy dietary fats are related to risk of GDM.

DESIGN

A prospective study was conducted in 13,475 women who reported a singleton pregnancy between 1991 and 2001 in the Nurses' Health Study II. In these women, 860 incident GDM cases were reported. The adjusted RR of GDM was estimated for quintiles of total fat, specific fat, and the source of fat intakes by pooled logistic regression.

RESULTS

Higher animal fat and cholesterol intakes were significantly associated with increased GDM risk. Across increasing quintiles of animal fat, RRs (95% CIs) for GDM were 1.00 (reference), 1.55 (1.20, 1.98), 1.43 (1.09, 1.88), 1.40 (1.04, 1.89), and 1.88 (1.36, 2.60) (P-trend = 0.05). Corresponding RRs (95% CIs) for dietary cholesterol were 1.00 (reference), 1.08 (0.84, 1.32), 1.02 (0.78, 1.29), 1.20 (0.93, 1.55), and 1.45 (1.11, 1.89) (P-trend = 0.04). The substitution of 5% of energy from animal fat for an equal percentage of energy from carbohydrates was associated with significantly increased risk of GDM [RR (95% CI): 1.13 (1.08, 1.18); P < 0.0001]. No significant associations were observed between dietary polyunsaturated fat, monounsaturated fat, or trans fat intakes and GDM risk.

CONCLUSION

Higher prepregnancy intakes of animal fat and cholesterol were associated with elevated GDM risk.

Changes in the Serum Level of High Density Lipoprotein-cholesterol after Smoking Cessation among Adult Men

Background

Smoking and obesity are known risk factors for cardiovascular diseases, while low serum levels of high density lipoprotein-cholesterol is an independent risk factor for mortality from ischemic heart diseases. This study examines changes in the serum level of high density lipoprotein-cholesterol depending on changes in the state of smoking and body mass index.

Methods

A survey and blood check-up were conducted on medical examination, along with acts of smoking among male adults of 25 years or older who visited the health promotion center of Daegu Medical Center from 2007 to 2010, and the results were analyzed. The subjects were divided into two different groups, current smokers and abstainers, and body mass index, total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, and triglycerides for three years were compared in both groups. Changes between the first and second visits in body mass index and lipid profiles of the two groups were compared to analyze changes after abstaining.

Results

The subject group which showed a significant increase in high density lipoprotein-cholesterol level was only abstainers whose body mass index had decreased by more than 0.5 kg/m².

Conclusion

Smoking cessation increases serum levels of high density lipoprotein-cholesterol. If reduction of body mass index and smoking cessation are combined, the risk of cardiovascular disease will be lower in proportion to the increase in serum high density lipoprotein.

A prospective study of prepregnancy dietary iron intake and risk for gestational diabetes mellitus

OBJECTIVE

It is important to identify modifiable factors that may lower gestational diabetes mellitus (GDM) risk. Dietary iron is of particular interest given that iron is a strong prooxidant, and high body iron levels can damage pancreatic β-cell function and impair glucose metabolism. The current study is to determine if prepregnancy dietary and supplemental iron intakes are associated with the risk of GDM.

RESEARCH DESIGN AND METHODS

A prospective study was conducted among 13,475 women who reported a singleton pregnancy between 1991 and 2001 in the Nurses' Health Study II. A total of 867 incident GDM cases were reported. Pooled logistic regression was used to estimate the relative risk (RR) of GDM by quintiles of iron intake controlling for dietary and nondietary risk factors.

RESULTS

Dietary heme iron intake was positively and significantly associated with GDM risk. After adjusting for age, BMI, and other risk factors, RRs (95% CIs) across increasing quintiles of heme iron were 1.0 (reference), 1.11 (0.87-1.43), 1.31 (1.03-1.68), 1.51 (1.17-1.93), and 1.58 (1.21-2.08), respectively (P for linear trend 0.0001). The multivariate adjusted RR for GDM associated with every 0.5-mg per day of increase in intake was 1.22 (1.10-1.36). No significant associations were observed between total dietary, nonheme, or supplemental iron intake and GDM risk.

CONCLUSIONS

These findings suggest that higher prepregnancy intake of dietary heme iron is associated with an increased GDM risk.

Associations among smoking status, lifestyle and lipoprotein subclasses

BACKGROUND

The relationship between cigarette smoking and cardiovascular disease is well established, yet the underlying mechanisms remain unclear. Although smokers have a more atherogenic lipid profile, this may be mediated by other lifestyle-related factors. Analysis of lipoprotein subclasses by the use of nuclear magnetic resonance spectroscopy (NMR) may improve characterisation of lipoprotein abnormalities.

OBJECTIVE

We used NMR spectroscopy to investigate the relationships between smoking status, lifestyle-related risk factors, and lipoproteins in a contemporary cohort.

METHODS

A total of 612 participants (360 women) aged 40-69 years at baseline (1990-1994) enrolled in the Melbourne Collaborative Cohort Study had plasma lipoproteins measured with NMR. Data were analysed separately by sex.

RESULTS

After adjusting for lifestyle-related risk factors, including alcohol and dietary intake, physical activity, and weight, mean total low-density lipoprotein (LDL) particle concentration was greater for female smokers than nonsmokers. Both medium- and small-LDL particle concentrations contributed to this difference. Total high-density lipoprotein (HDL) and large-HDL particle concentrations were lower for female smokers than nonsmokers. The proportion with low HDL particle number was greater for female smokers than nonsmokers. For men, there were few smoking-related differences in lipoprotein measures.

CONCLUSION

Female smokers have a more atherogenic lipoprotein profile than nonsmokers. This difference is independent of other lifestyle-related risk factors. Lipoprotein profiles did not differ greatly between male smokers and nonsmokers.

Reduced high-density lipoprotein level is linked to worse ankle brachial index and peak oxygen uptake in postmenopausal women with peripheral arterial disease

Women with peripheral arterial disease (PAD) have more limited physical function than men but the mechanisms involved are not clear. We determined whether alterations in lipid components, such as decreased high-density lipoprotein cholesterol (HDL-C), are associated with worsening intermittent claudication (IC) in postmenopausal women with PAD. Our cross-sectional cohort study included 69 postmenopausal women with IC (Fontaine stage II). A treadmill test was used to measure initial claudication distance (ICD), absolute claudication distance (ACD), peak oxygen uptake, and ankle systolic blood pressure. High-density lipoprotein cholesterol correlated with ankle brachial index ([ABI]; R = .29, P = .019). No other lipid profile components were associated with exercise performance and hemodynamic measures. Among women with HDL-C <50 mg/dL (n = 43), the median peak oxygen uptake level was significantly lower (P = .021) relative to women with normal HDL-C >50 mg/dL (n = 26). Lower HDL-C levels are associated with worse ABI and decreased peak oxygen uptake in postmenopausal women with PAD.

Relationship of the polyunsaturated to saturated fatty acid ratio to cardiovascular risk factors and metabolic syndrome in Japanese: the INTERLIPID study

AIM

There have been few studies on the relationships of the dietary polyunsaturated to saturated fatty acid ratio (P/S) to cardiovascular risk factors and metabolic syndrome. We hypothesized that there would be favorable relationships.

METHODS

Metabolic cardiovascular risk factors from dietary nutrient intake were investigated in 1,004 men and women aged 40-59 years from 4 population samples of Japanese. Multiple linear regression analysis was used to examine the relationship of the dietary P/S ratio to the following risk factors: hemoglobin A1c, blood pressure, serum triglycerides, LDL and total cholesterol, and HDL-cholesterol. Adjusted odds ratio of having metabolic syndrome was also calculated.

RESULTS

The dietary P/S ratio was significantly and inversely related to serum total and LDL cholesterol with control for possible confounding variables. We did not find any significant relationship between the P/S ratio and single metabolic risk factors or the prevalence of metabolic syndrome.

CONCLUSIONS

Managing the P/S ratio is important to control serum LDL-cholesterol; however, increasing the P/S ratio may not improve metabolic risk factors. Other countermeasures, such as weight control, greater physical activity, and smoking cessation should be recommended to prevent and control metabolic syndrome.

Prospective study of pre-gravid sugar-sweetened beverage consumption and the risk of gestational diabetes mellitus

OBJECTIVE

Consumption of sugar-sweetened beverages (SSBs) was related to an elevated risk of type 2 diabetes and insulin resistance in several recent studies among middle- or older-aged populations. Studies on SSB consumption and glucose intolerance among pregnant women, however, are lacking. We therefore examined the association between regular SSB consumption before pregnancy and the risk of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

This was a prospective study among 13,475 U.S. women who reported at least one singleton pregnancy between 1992 and 2001 in the Nurses' Health Study II. GDM was self-reported and validated by medical record review in a subsample. Cox proportional hazards models with multivariate adjustments were applied to examine the association of SSB consumption with GDM risk.

RESULTS

During 10 years of follow-up, 860 incident GDM case subjects were identified. After adjustment for age, parity, race, physical activity, smoking, alcohol intake, prepregnancy BMI, and Western dietary pattern, intake of sugar-sweetened cola was positively associated with the risk of GDM, whereas no significant association was found for other SSBs and diet beverages. Compared with women who consumed <1 serving/month, those who consumed >or=5 servings/week of sugar-sweetened cola had a 22% greater GDM risk (relative risk 1.22 [95% CI 1.01-1.47]).

CONCLUSIONS

Findings from this study suggest that prepregnancy higher consumption of sugar-sweetened cola (>or=5 servings/week) is associated with an elevated GDM risk, whereas no significant association with GDM risk was observed for other SSBs and diet beverages.

Pioglitazone decreases postprandial accumulation of remnant lipoproteins in insulin-resistant smokers

BACKGROUND

Fasting hypertriglyceridaemia has been reported to occur commonly in cigarette smokers and is thought to increase cardiovascular disease (CVD) risk in these individuals. More recently, it has been suggested that an increase in non-fasting triglycerides, rather than fasting hypertriglyceridaemia, is an independent CVD risk factor.

METHODS

In this study, we divided 24 smokers into insulin-resistant (IR) and insulin-sensitive (IS) groups by determining their steady-state plasma glucose concentrations during the insulin suppression test and compared fasting and daylong postprandial accumulation of total triglycerides and remnant lipoprotein (RLP) concentrations, before and after 3 months of pioglitazone (PIO) administration.

RESULTS

The two groups were similar in age, body mass index, race and gender distribution, but differed dramatically in insulin sensitivity. Baseline fasting and postprandial triglyceride, RLP cholesterol and RLP triglyceride concentrations were significantly higher in the IR smokers (p=0.01 to <0.01). Insulin resistance [corrected] and both fasting and postprandial triglyceride and RLP triglyceride levels decreased significantly (p=0.05 to 0.01) [corrected] in PIO-treated IR smokers, without any significant increase in weight instead of insulin sensitivity and both fasting and postprandial triglyceride and RLP triglyceride levels decreased significantly (p = 0.05 to, 0.01) in PIO-treated IR smokers, without any significant increase in weight. [corrected]

CONCLUSIONS

The postprandial accumulation of RLP particles is increased in the IR subset of smokers and is likely to contribute to the increased CVD risk in these individuals. Furthermore, PIO administration provides a possible therapeutic approach to decreasing postprandial lipaemia and CVD risk in IR smokers who are unwilling or unable to stop smoking.

The role of exercise in minimizing postprandial oxidative stress in cigarette smokers

Cigarette smoking continues to pose a significant health burden on society. Two well-described mechanistic links associating smoking with morbidity and mortality include elevated blood lipids and increased oxidative stress. These variables have traditionally been measured while an individual is fasting, but evidence suggests that postprandial lipemia and oxidative stress provide more important information concerning susceptibility to disease, in particular cardiovascular disease. Cigarette smokers have elevated levels of biomarkers of oxidative stress at rest and experience impaired postprandial lipid and glucose metabolism. We have confirmed these findings while noting an exaggerated oxidative stress response to high-fat feeding. Smoking cessation is without question the best approach to minimizing smoking-induced ill health and disease, but success rates among those who attempt to quit are dismal. Other means to decrease a smoker's susceptibility to oxidative stress-related disease are needed. We propose that exercise may aid in attenuating postprandial oxidative stress, and we do so in 3 distinct ways. First, exercise stimulates an increase in endogenous antioxidant enzyme activity. Second, exercise improves blood triglyceride clearance via a reduced chylomicron-triglyceride half-life and an enhanced lipoprotein lipase activity. Third, exercise improves blood glucose clearance via an enhanced glucose 4 transport protein translocation and protein content, as well as insulin-insulin receptor binding and postreceptor signaling. Improvements in antioxidant status, as well as lipid and glucose processing, may aid greatly in minimizing feeding-induced oxidative stress in smokers. If so, and in accordance with the recent joint initiative of the American College of Sports Medicine and the American Medical Association, exercise may be viewed as a "medicine" for cigarette smokers at increased risk for postprandial oxidative stress. Research into this area may provide insight into the potential benefits of exercise for this purpose.

Pioglitazone administration decreases cardiovascular disease risk factors in insulin-resistant smokers

Insulin sensitivity varies in cigarette smokers, and there is evidence that cardiovascular disease (CVD) risk is greatest in those smokers who are also insulin resistant. To extend these observations, we sought to (1) compare CVD risk factors in smokers who do not plan to stop smoking, divided into insulin-resistant (IR) and insulin-sensitive (IS) subgroups, and (2) evaluate the ability of drug-induced changes in insulin sensitivity to decrease CVD risk. Thirty-six cigarette smokers were divided into IR (n = 19) and IS (n = 17) subgroups by determining their steady-state plasma glucose (SSPG) concentrations during the insulin suppression test (the higher the SSPG, the more insulin resistant the individual). In addition, baseline measurements were made of fasting lipid and lipoprotein concentrations; inflammatory markers; and daylong glucose, insulin, and free fatty acid responses to test meals. All subjects were treated with pioglitazone for 12 weeks, after which all baseline measurements were repeated. Baseline triglyceride and high-density lipoprotein cholesterol concentrations were significantly different in IR as compared with IS smokers (P < .05) both before and after adjustment for differences in sex and body mass index. After pioglitazone treatment, SSPG concentration significantly fell in the IR smokers (P < .001), associated with a significant improvement in the atherogenic lipoprotein profile seen at baseline (P < or = .03) and a decrease in soluble intercellular adhesion molecule 1 and C-reactive protein concentrations (P = .01 and .02, respectively), whereas the IS smokers only had a significant increase in high-density lipoprotein cholesterol (P = .004) and a decrease in soluble intercellular adhesion molecule 1 (P = .02) and CRP (P = .07) levels. In conclusion, cigarette smokers have profound differences in CVD risk factors related to their degree of insulin sensitivity. It is suggested that, in addition to smoking cessation efforts, attention should be given to identifying the subgroup of smokers most at risk for CVD, but unwilling or unable to stop smoking, and to initiating appropriate therapeutic interventions to decrease CVD in this high-risk group.

The relationship between insulin resistance and dyslipidaemia in cigarette smokers

AIM

Considerable evidence shows that cigarette smokers tend to have the dyslipidemic pattern of high plasma triglyceride (TG) and low high-density lipoprotein cholesterol (HDL-C) concentrations, a highly atherogenic lipoprotein profile also typical of the insulin-resistant state even in the absence of cigarette smoking. However, because cigarette smokers are frequently insulin resistant, it is unclear if this dyslipidaemia is secondary to smoking, per se, or simply to the fact that smokers tend to be insulin resistant. The present study was initiated to determine whether this dyslipidaemia prevalent in cigarette smokers and characteristic of insulin-resistant individuals is a function of cigarette smoking or of insulin resistance.

METHODS

As measured using vertical auto profile-II methodology, the lipid and lipoprotein concentrations were compared in 34 cigarette smokers divided into insulin-sensitive and insulin-resistant subgroups. The two groups were similar in age and body mass index, differing only in their insulin-mediated glucose uptake as quantified by the steady-state plasma glucose concentration determined during the insulin suppression test.

RESULTS

While levels of TG and very low-density lipoprotein cholesterol (VLDL-C) were significantly elevated in insulin-resistant cigarette smokers, total cholesterol (C), low-density lipoprotein cholesterol (LDL-C), narrow-density (ND) LDL-C, intermediate-density lipoprotein-C (IDL-C), HDL-C and non-HDL-C were not different in the two groups. The insulin-resistant smokers also had a preponderance of small, dense LDL particles, while the reverse was true of the insulin-sensitive cigarette smokers.

CONCLUSIONS

These data suggest that the dyslipidaemia previously attributed to smoking occurs primarily in those smokers who are also insulin resistant.

Adiponectin and insulin resistance in young and healthy smokers

Smoking is closely associated with insulin resistance, though the mechanism is not clear. Adiponectin, a novel anti-atherosclerotic and anti-inflammatory adipose tissue product, which is closely associated with insulin resistance, was reported to be low in smokers with cofactors for atherosclerosis. However, the effects of smoking on circulating adiponectin levels in otherwise healthy people are unknown. In this study, a case control design was implemented to search for the effect of smoking on plasma adiponectin and insulin sensitivities in healthy people. Sixty-four healthy male smokers, with no family history of hypertension and diabetes mellitus were compared with appropriate 36 age and body mass index matched controls. Both the patients and controls were the soldiers of a troop with regular daily physical activity. Plasma adiponectin, high sensitive C-reactive protein (hsCRP), insulin and lipid levels, and insulin sensitivity as assessed by homeostasis model assessment index (HOMA) of the smokers were measured and compared with those of the controls. The plasma adiponectin, hsCRP, insulin levels and HOMA indexes of the two groups were similar. These parameters were not affected by the amount of cigarettes per day. HDL-cholesterol levels were lower (p = 0.01) and systolic blood pressures were higher (p = 0.02) in the smokers. These results indicate that smoking may not affect plasma adiponectin and insulin levels in young and healthy men with high exercise capacity.

Chromium picolinate may favorably influence the vascular risk associated with smoking by combating cortisol-induced insulin resistance

Smoking promotes insulin resistance and other features - excepting hypertension - of the insulin resistance syndrome; these effects appear to reflect chronic nicotine exposure. The adverse impact of smoking on insulin function may be a prominent mediator of the excess vascular risk associated with smoking. Although the mechanistic basis of nicotine-induced insulin resistance remains to be clarified, increased secretion of ACTH and cortisol seems likely to play an important role in this regard. It is therefore intriguing to note that supplemental chromium picolinate has been reported to have a rapid and substantial favorable impact on glycemic control in patients with corticosteroid-induced diabetes. In dexamethasone-treated rats, high doses of this compound have been shown to markedly improve insulin sensitivity. Thus, if these initial reports are confirmable, ample intakes of bioactive chromium may have the potential to reverse the negative influence of corticosteroids on insulin signaling. Such an effect might have utility not only for smokers, but for others in whom chronic up-regulation of the hypothalamic-pituitary-adrenal axis compromises vascular health. The impact of chromium picolinate on smoking- or nicotine-induced insulin resistance merits study.

Do gene-environment interactions influence fasting plasma lipids? A study of twins

BACKGROUND

The aims of this study were to determine the influence of smoking, alcohol consumption, physical activity and hormone replacement therapy (HRT) on lipids, independently of genetic factors, and to detect whether gene-environment interactions influence these associations.

MATERIALS AND METHODS

Fasting plasma total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, apolipoproteins AI and B and lipoprotein(a) were measured in 685 female twins (96 monozygotic, 230 dizygotic pairs and 33 singletons).

RESULTS

Smokers had higher triglyceride and lower HDL cholesterol levels than never-smokers (P < 0.001). After controlling for genetic influences, smoking accounted for 0.35 mmol L(-1) and 0.22 mmol L(-1) differences in triglyceride and HDL cholesterol levels, respectively (P < 0.005), remaining significant after excluding alcohol-discordant twin pairs. In a gene-environment interaction analysis, the association between smoking and triglycerides was exaggerated in subjects at high genetic risk of hypertriglyceridaemia (interaction P=0.04). All levels of alcohol consumption were associated with higher HDL cholesterol levels than abstinence, but only moderate alcohol consumers had lower LDL cholesterol and triglyceride levels. In monozygotic twins concordant for smoking, an alcohol intake > 10 units week(-1) accounted for a 0.32 mmol L(-1) difference in LDL cholesterol, independently of genetic effects (P=0.04). In postmenopausal women, those using HRT had 0.54 mmol L(-1) lower LDL cholesterol and 0.21 micromol L(-1) lower lipoprotein(a) levels than nonusers (P < 0.001 and P=0.04, respectively); these differences were attenuated after accounting for genetic effects in monozygotic twins. Although physically active subjects had higher levels of HDL cholesterol than nonactive subjects, this was nonsignificant after adjusting for genetic factors.

CONCLUSIONS

Smoking-induced aberrations in HDL cholesterol and triglycerides and alcohol-related differences in LDL cholesterol were independent of genetic influences. The association between smoking and hypertriglyceridaemia was accentuated in high genetic risk individuals.

The metabolic syndrome in smokers. The D.E.S.I.R. study

OBJECTIVES

To test the hypothesis that smokers have a higher frequency of the metabolic syndrome, and a syndrome with different characteristics than non-smokers.

MATERIAL AND METHODS

The 2,569 men and 2,637 women included in the D.E.S.I.R. study, aged 30-64 years, volunteers from ten French Social Security Health Examination Centres, were studied. The World Health Organization definition of the metabolic syndrome was adapted for this analysis, and insulin resistance was defined by a concentration above the 75(th) centile of the sex-specific distribution of fasting insulin.

RESULTS

28.1% of men and 15.1% of women were current smokers. The metabolic syndrome was twice as frequent in men than in women (22.8% vs 11.0%). Smokers and never-smokers were compared in age stratified samples. In men, the frequencies of hyperglycaemia or hypoglycaemic treatment, dyslipidaemia, microalbuminuria, and central obesity were significantly higher in smokers and 22.5% of smokers and 15.3% of non-smokers had this syndrome (p=0.001). In women, only dyslipidaemia was more frequent in smokers; in contrast smokers had lower insulin concentrations and hence a lower frequency of hyperinsulinemia. The frequency of the syndrome did not differ between women who smoked and those who did not (6.3% vs 6.0%).

CONCLUSIONS

In men, the metabolic syndrome was more frequent in smokers than in non-smokers; in contrast, there was no difference for women. For both sexes, syndrome abnormalities tended to be more frequent in smokers than in non-smokers.

Insulin resistance and compensatory hyperinsulinemia: the key player between cigarette smoking and cardiovascular disease?

Hyperinsulinemia, dyslipidemia, and endothelial dysfunction are characteristic findings in insulin-resistant individuals, and all of these abnormalities have been identified as increasing cardiovascular disease (CVD) risk. Smokers tend to be relatively insulin resistant, hyperinsulinemic, and dyslipidemic, with evidence of endothelial dysfunction, as compared with nonsmokers, and recent epidemiologic data have suggested that CVD in smokers is primarily seen in those individuals who also have the characteristic findings of insulin resistance. Based on these observations, it is argued that insulin resistance and its consequences represent a major mechanistic link between cigarette smoking and CVD. It is also postulated that the enhanced CVD risk in smokers, resulting from hyperinsulinemia, abnormalities of lipoprotein metabolism, and endothelial dysfunction, will primarily be present in those smokers who are insulin resistant. As a corollary, it is suggested that CVD risk in individuals who cannot, or will not, stop smoking can be reduced by therapeutic efforts aimed at attenuating the adverse effects of insulin resistance and its consequences.

Periodontitis and diabetes interrelationships: role of inflammation

Diabetes mellitus is a systemic disease with several major complications affecting both the quality and length of life. One of these complications is periodontal disease (periodontitis). Periodontitis is much more than a localized oral infection. Recent data indicate that periodontitis may cause changes in systemic physiology. The interrelationships between periodontitis and diabetes provide an example of systemic disease predisposing to oral infection, and once that infection is established, the oral infection exacerbates systemic disease. In this case, it may also be possible for the oral infection to predispose to systemic disease. In order to understand the cellular/molecular mechanisms responsible for such a cyclical association, one must identify common physiological changes associated with diabetes and periodontitis that produce a synergy when the conditions coexist. A potential mechanistic link involves the broad axis of inflammation, specifically immune cell phenotype, serum lipid levels, and tissue homeostasis. Diabetes-induced changes in immune cell function produce an inflammatory immune cell phenotype (upregulation of proinflammatory cytokines from monocytes/polymorphonuclear leukocytes and downregulation of growth factors from macrophages). This predisposes to chronic inflammation, progressive tissue breakdown, and diminished tissue repair capacity. Periodontal tissues frequently manifest these changes because they are constantly wounded by substances emanating from bacterial biofilms. Diabetic patients are prone to elevated low density lipoprotein cholesterol and triglycerides (LDL/TRG) even when blood glucose levels are well controlled. This is significant, as recent studies demonstrate that hyperlipidemia may be one of the factors associated with diabetes-induced immune cell alterations. Recent human studies have established a relationship between high serum lipid levels and periodontitis. Some evidence now suggests that periodontitis itself may lead to elevated LDL/TRG. Periodontitis-induced bacteremia/endotoxemia has been shown to cause elevations of serum proinflammatory cytokines such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha), which have been demonstrated to produce alterations in lipid metabolism leading to hyperlipidemia. Within this context, periodontitis may contribute to elevated proinflammatory cytokines/serum lipids and potentially to systemic disease arising from chronic hyperlipidemia and/or increased inflammatory mediators. These cytokines can produce an insulin resistance syndrome similar to that observed in diabetes and initiate destruction of pancreatic beta cells leading to development of diabetes. Thus, there is potential for periodontitis to exacerbate diabetes-induced hyperlipidemia, immune cell alterations, and diminished tissue repair capacity. It may also be possible for chronic periodontitis to induce diabetes.

Cigarette smoking, blood pressure and serum lipids and lipoproteins in middle-aged women

The relationship of cigarette smoking with blood pressure and serum lipids and lipoproteins was studied in the 3934 middle-aged women aged 40 to 59 years. After adjusting age, body mass index (BMI), alcohol intake and physical activity scores, the mean systolic and diastolic blood pressures (SBP and DEP, respectively) did not indicate dose-dependent relationships. The largest significant mean differences in SBP (4.6 mmHg), DBP (3.9 mmHg), high density lipoprotein cholesterol (HDL-C) (9.6 mg/dL), ratio of total cholesterol to HDL-C (TC/HDL-C) (0.8), triglycerides (TG) (22.9 mg/dL) and the logarithmic transformation of TG (Log TG) (0.26) were found between the non-smokers and smokers. When age, BMI, alcohol intake and physical activity scores were included in the forward stepwise multiple regression analyses, there were negative relationships found for cigarette smoking and SBP, DBP and HDL-C and positive relationships for cigarette smoking and TC/HDL-C, TG, Log TG and low density lipoprotein cholesterol. Although the results are somewhat variable, the present study shows cigarette smoking is negatively associated with SBP and DBP and unfavorably associated with serum lipids and lipoproteins in middle-aged women.

Relationship of cigarette smoking with blood pressure, serum lipids and lipoproteins in young Japanese women

1. The relationship of cigarette smoking with blood pressure and serum lipids and lipoproteins was studied in 1062 young Japanese women aged 20-39 years of age. 2. After adjusting for age, body mass index (BMI), alcohol intake and physical activity scores, the mean systolic and diastolic blood pressures (SBP and DBP, respectively) did not indicate dose-dependent relationships with cigarette smoking. The largest significant mean differences in SBP (3.5%; P < 0.001), DBP (6.2%; P < 0.018), high-density lipoprotein-cholesterol (HDL-C; 13.2%; P < 0.005), ratio of total cholesterol to HDL-C (13.9%; P < 0.022), triglycerides (TG; 24.1%; P < 0.001) and the logarithmic transformation of TG (log TG; 5.6%; P < 0.001) were found between non-smokers and smokers. 3. When age, BMI, alcohol intake and physical activity scores were included in the forward step-wise multiple regression analysis, there were negative relationships found for cigarette smoking and SBP and DBP and positive relationships for cigarette smoking and TG and log TG. 4. Although the results are somewhat variable, the present study shows that cigarette smoking is negatively associated with SBP and DBP and that there is an association between cigarette smoking and serum lipids and lipoproteins and that smoking has an unfavourable effect on these parameters in young Japanese women.

Serum lipids in postmenopausal or perimenopausal women using estrogen alone, estrogen with levonorgestrel, or estrogen with norethisterone, compared with nonusers: results from a cross-sectional study in two Norwegian counties 1985-1988

The aim of this study was to compare, in a population setting of postmenopausal or perimenopausal women aged 40 to 54, the levels of serum lipids in women using different hormone replacement therapy (HRT) regimens with women using no sex hormones. There was no unequivocal tendency of a more healthy lifestyle among those using HRT than among nonusers. Any type of regimen was associated with a lower mean level of total and calculated low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol was 0.08 mmol/L (5.2%) higher in those using estrogen alone, 0.07 mmol/L (4.5%) higher in users of HRT with norethisterone, and 0.07 mmol/L (4.5%) lower in users of HRT with levonorgestrel, compared with nonusers. The ratio of total-to-HDL cholesterol was lower by 0.37 (6.1%) in those using estrogen alone, by 0.65 (12.3%) in those using HRT with norethisterone, and by 0.24 (5.3%) in those using estrogen with levonorgestrel. There was no association between body mass index and HDL-cholesterol among women who used HRT with norethisterone, whereas an inverse relationship was present in those using estrogen alone and in nonusers (P [interaction] < 0.05).

Sex and topographic differences in associations between large-artery wall thickness and coronary risk profile in a French working cohort: the AXA Study

Previous reports have investigated associations between carotid intima-media thickness (IMT) and cardiovascular risk factors. Our objective was to investigate this question in greater depth by measuring both femoral and carotid IMT in relation to sex and multifactorial coronary risk. We investigated carotid and femoral artery IMT by using ultrasonography in 326 men and 462 women, 17 to 65 years old. We also evaluated body mass index, blood pressure, blood lipids, glucose, smoking, and Framingham coronary risk. In both vessels, IMT was lower in women than in men. Significant relations between carotid and femoral IMT existed with age and most risk factors in both sexes. After adjustment for age, carotid IMT was related to risk factors in both sexes except for diastolic blood pressure, HDL cholesterol, and smoking in women, whereas femoral IMT was related to triglycerides and smoking in both sexes, systolic blood pressure and blood glucose in men, and total and HDL cholesterol in women. Significant unadjusted and age-adjusted relations of Framingham risk existed with carotid and femoral IMT in both sexes, but slopes of these relations were greater (1) before than after age adjustment, (2) in men than in women at both sites, except the femoral artery after age adjustment, and (3) at the carotid than at the femoral site in both sexes before age adjustment. Carotid IMT in men appears to be a more powerful predictor than it is in women and femoral IMT in both sexes in reflecting multifactorial coronary risk burden, but these differences are partly conditional on age.

Cardiovascular risk factors and behavior lifestyles of young women: implications from findings of the Bogalusa Heart Study

The primary purposes of this article are to highlight important issues related to cardiovascular risk factors and behavior life-styles in young women and to examine racial (black-white) differences in risk factors that relate to cardiovascular disease. In childhood, some girls show cardiovascular risk factors of higher blood pressure levels, dyslipidemia, and obesity, all of which continue into young adulthood. Factors that contribute to abnormal risk factors are a high-saturated fat diet, excess energy intake related to inactivity, and cigarette smoking. Trends of obesity are documented; and young white girls are continuing to use tobacco, more so than boys and black girls. Although the onset of clinical cardiovascular disease is delayed in women, the stage is set in childhood for the development of early cardiovascular risk.

Smoking is associated with higher cardiovascular risk in young women than in men: the Tecumseh Blood Pressure Study

BACKGROUND

Tobacco smoking is associated with a higher prevalence of atherosclerosis and respiratory disease.

OBJECTIVE

To investigate differences between hemodynamic and biochemical findings in smokers and nonsmokers in the two sexes separately in the Tecumseh population.

METHODS

We studied 851 subjects. They were divided according to smoking habits into group 1, nonsmokers (258 men and 234 women); and group 2, smokers (185 men and 174 women).

RESULTS

Unpaired Student's t-tests and nonparametric tests were performed to determine the between-group P-values. Only hematocrit differed significantly between smokers and nonsmokers in both sexes (43.9 +/- 0.2 and 44.6 +/- 9.3%, P < 0.05 in men; 39.2 +/- 0.3 and 40.3 +/- 0.3%, P = 0.007 in women, respectively in nonsmokers and smokers). Triglycerides (80.6 +/- 3.8 and 99.6 +/- 4.3 mg/dl, P < 0.001), left ventricular mass index (95.4 +/- 1.9 and 100.0 +/- 1.2 g/m2, P = 0.008), and posterior wall thickness (9.5 +/- 0.1 and 9.71 +/- 0.01 mm, P = 0.044) were elevated and high-density lipoproteins were decreased (48.7 +/- 0.8 and 44.5 +/- 0.9 mg/dl, P < 0.01) only in women smokers. After adjustment for home systolic blood pressure and body mass index the differences in women remained significant except for posterior wall thickness.

CONCLUSION

Tobacco smoking is deleterious to both sexes but it appears to be particularly harmful to women. Our data can, in part, explain why the relative risk of myocardial infarction is higher in women than it is in men.

Effect of diet and physical exercise intervention programmes on coronary heart disease risk in smoking and non-smoking men in Sweden

STUDY OBJECTIVE

To investigate differences between smokers and non-smokers in health behaviour, cardiovascular risk factors, coronary heart disease (CHD) risks, health knowledge, health attitudes, and compliance with a CHD prevention programme.

DESIGN

Differences between smokers and non-smokers were studied via medical examinations, questionnaires, physical exercise activity logs, and food record sheets. Data were analysed using univariate and multivariate analyses. The five and 10 year CHD risks were assessed using the Framingham CHD risk estimate.

SETTING

The Karolinska Hospital, Stockholm, and Sollentuna Primary Health Centre, Sollentuna, Sweden.

PARTICIPANTS

The analyses were based on 158 healthy smoking and non-smoking men aged 35-60 years with raised cardiovascular risk factors who enrolled in controlled, randomised six month diet and exercise programmes.

MAIN RESULTS

Discriminant analysis suggested that smokers, compared with non-smokers, were characterised by a higher alcohol energy percent, lower HDL cholesterol concentration, lower systolic blood pressure, and a higher plasminogen activator inhibitor-1 (PAI-1) value. Knowledge of the risk factors for CHD was not a discriminating factor. Both smokers and non-smokers increased the exercise taken, improved their diet, and lowered their CHD risk. Before, as well as after the intervention, smokers had a higher CHD risk than non-smokers.

CONCLUSIONS

The best CHD prevention action that could be taken by smokers would of course be to quit smoking. Those who cannot stop should be encouraged to improve their diet and increase the amount of physical exercise they take in order to reduce the health hazards of their smoking behaviour.

A lipoprotein lipase mutation (Asn291Ser) is associated with reduced HDL cholesterol levels in premature atherosclerosis

A reduction of high density lipoprotein cholesterol (HDC) is recognized as an important risk factor for coronary artery disease (CAD). We now show in approximately 1 in 20 males with proven atherosclerosis that an Asn291Ser mutation in the human lipoprotein lipase (LPL) gene is associated with significantly reduced HDL levels (P = 0.001) and results in a significant decrease in LPL catalytic activity (P < 0.0009). The relative frequency of this mutation increases in those patients with lower HDL cholesterol levels. In vitro mutagenesis and expression studies confirm that this change is associated with a significant reduction in LPL activity. Our data support the relationship between LPL activity and HDL-C levels, and suggest that a specific LPL mutation may be a factor in the development of atherosclerosis.

Increased level of hemoglobin A1c, but not impaired insulin sensitivity, found in hypertensive and normotensive smokers

Smoking is associated with an abnormal plasma lipoprotein pattern. Recently, both insulin resistance and normal insulin action have been reported in smokers. In a total of 191 hypertensive and normotensive subjects recruited from a health survey, serum lipoprotein lipids, glucose tolerance (by intravenous glucose tolerance test (IVGTT), insulin secretion, and insulin sensitivity (euglycemic insulin clamp) were compared in the 41 smokers and 150 nonsmokers. Subjects were examined in the morning during a fasting state and after abstinence from smoking for 10 to 12 hours. Smokers showed a higher level of hemoglobin A1c (HbA1c) as compared with nonsmokers, 4.9% versus 4.7% (P < .05). There were no significant differences in fasting glucose, insulin, or insulin-mediated glucose disposal. However, a number of indices of insulin sensitivity tended to show enhanced insulin action among smokers. Only lower glucose and insulin values during the late phase (40 to 90 minutes) of the IVGTT reached statistical significance. Compared with nonsmokers, smokers had an expected higher level of serum triglycerides (2.1 v 1.8 mmol/L, P < .05) and an increased low-density lipoprotein (LDL) to high-density lipoprotein (HDL) cholesterol ratio (4.5 v 3.9, P < .05). These differences between smokers and nonsmokers were similar in both hypertensives and normotensives. In conclusion, smokers examined in the abstinence phase showed no signs of impaired insulin action. Lipoprotein abnormalities and elevated HbA1c may be caused in part by the insulin resistance induced during acute smoking and therefore may be quantitatively related to the time exposed to smoking. The effect on insulin sensitivity appears to be reversible over 10 to 12 hours.