Age Differences in the Relationship between Secondhand Smoke Exposure and Risk of Metabolic Syndrome: A Meta-Analysis

Sex difference in the associations among secondhand smoke with metabolic syndrome in non-smokers in a large Taiwanese population follow-up study

Close associations among secondhand smoke (SHS) and metabolic syndrome (MetS) and its components have been demonstrated, however sex differences in these associations remain unclear. We collected 121,364 participants from the Taiwan Biobank, and excluded those with smoking history, the remaining 88,297 participants (male: 18,595; female: 69,702; mean age 50.1 ± 11.0 years) were included. SHS exposure was evaluated based on self-reported questionnaires. SHS was associated with MetS (odds ratio [OR], 1.268, p < 0.001 for males vs. 1.180, p < 0.001 for females), abdominal obesity (OR, 1.234, p < 0.001 for males vs. 1.199, p < 0.001 for females), low high-density lipoprotein cholesterol (OR, 1.183, p = 0.008 for males vs. 1.094, p = 0.011 for females), hyperglycemia (OR, 1.286, p < 0.001 for males vs. 1.234, p < 0.001 for females), but not with hypertriglyceridemia. SHS was associated with high blood pressure (BP) (OR, 1.278, p < 0.001) only in males, but not in females. Furthermore, significant interactions were found between sex x SHS on MetS (p = 0.023), abdominal obesity (p = 0.032), and elevated BP (p < 0.001). Moreover, the participants who were exposed to SHS for ≥1 hour per week were associated with a higher risk (OR = 1.316, p = 0.001 in males vs. OR = 1.220, p < 0.001 in females) of MetS compared to those with no exposure. These results showed an association between SHS and a high OR for MetS in both the males and females. Furthermore, sex differences were identified in the associations between SHS and MetS and its components, and SHS was more closely related to MetS, abdominal obesity, and high BP in males than in females.

The Effects of Smoking on the Diagnostic Characteristics of Metabolic Syndrome: A Review

Metabolic syndrome is a growing epidemic that increases the risk for cardiovascular disease, diabetes, stroke, and mortality. It is diagnosed by the presence of three or more of the following risk factors: 1) obesity, with an emphasis on central adiposity, 2) high blood pressure, 3) hyperglycemia, 4) dyslipidemia, with regard to reduced high-density lipoprotein concentrations, and 5) dyslipidemia, with regard to elevated triglycerides. Smoking is one lifestyle factor that can increase the risk for metabolic syndrome as it has been shown to exert negative effects on abdominal obesity, blood pressure, blood glucose concentrations, and blood lipid profiles. Smoking may also negatively affect other factors that influence glucose and lipid metabolism including lipoprotein lipase, adiponectin, peroxisome proliferator-activated receptors, and tumor necrosis factor-alpha. Some of these smoking-related outcomes may be reversed with smoking cessation, thus reducing the risk for metabolic disease; however, metabolic syndrome risk may initially increase post cessation, possibly due to weight gain. Therefore, these findings warrant the need for more research on the development and efficacy of smoking prevention and cessation programs.

Pre- and postnatal exposure to secondhand tobacco smoke and cardiometabolic risk at 12 years: Periods of susceptibility

BACKGROUND

To identify periods of heightened susceptibility to the association of secondhand tobacco smoke (SHS) exposure with cardiometabolic (CM) risk at age 12 years.

METHODS

We used data from 212 adolescents from the HOME Study, a prospective pregnancy and birth cohort in Cincinnati, OH. Using multiple informant models, we estimated associations of maternal serum cotinine (mean of concentrations at 16 and 26 weeks of pregnancy) and children's serum cotinine concentrations (mean of concentrations at ages 1, 2, 3, and 4 years) with a CM risk summary score constructed of five risk components measured at age 12 years. We determined if these associations differed for pre- and postnatal exposure periods, and adolescent's sex.

RESULTS

We found some evidence that the cotinine-outcome associations differed by exposure period and sex. Postnatal, but not prenatal, cotinine was associated with higher CM risk scores and individual CM risk component values (interaction p-values = 0.04 to 0.35). Each 10-fold increase in postnatal cotinine was associated with 0.57 (95% CI: 0.32, 1.45), 0.09 (95% CI: 0.13, 0.31), 0.14 (-0.08, 0.35), 0.07 (95% CI: 0.34, 0.48), and 0.11 (95% CI: 0.04, 0.27) higher CM risk, HOMA-IR, TG to HDL-C ratio, leptin to adiponectin ratio, and visceral fat area. Postnatal cotinine was associated with higher visceral fat area among females but not males (sex × period × cotinine interaction p-value = 0.01).

CONCLUSIONS

Serum cotinine concentrations during the postnatal period had greater influence on adolescent's CM risk compared to the prenatal period, and these associations may be sex-specific. This study reinforces the need for ongoing public health interventions to minimize children's exposure to SHS.

The association between urinary cotinine level and metabolic syndrome profiles among adolescents: findings from the Ewha Birth and growth study

BACKGROUND

Secondhand smoke (SHS) exposure among adolescents who are still developing can negatively affect their physical and psychological health, including metabolic syndrome (MetS), which is a risk factor for cardiovascular disease. However, the relationship between exposure to SHS and MetS in adolescence has not been evaluated.

METHODS

A total of 240 subjects aged 13-15 years who were followed up in the Ewha Birth and Growth Study were included in this study. Using the urinary cotinine level, the participants' exposure to SHS was divided into tertiles, and the continuous MetS score (cMetS) and its components were compared among the three groups using a generalized linear model and trend analysis. Univariate and multivariate linear regression analyses were performed. We adjusted for several confounding variables including sex, father's education level, father's current alcohol consumption status, moderate physical activity, and overweight status.

RESULTS

The association between cMetS and the urinary cotinine level was not significant. However, the higher the urinary cotinine level, the lower the high-density lipoprotein cholesterol (HDL-C) level. In particular, the significance of the HDL-C level was maintained after adjusting for covariates.

CONCLUSIONS

This study supports an association between SHS exposure and the components of MetS in adolescents aged 13-15 years, and it suggests the need to address SHS exposure in adolescents to reduce the cardiovascular risk in later life.

Diseases, health behaviors, psychological health and associated factors among women aged 50-70 years: a cross-sectional study in Hunan Province, China

This cross-sectional study identified 2, 585 women aged 50-70 with certain diseases, health behaviors and psychological health problems among a representative and community-conducted sample of women in Hunan Province of China. It disclosed their poor health status: 51.0% had chronic diseases, 49.6% had gynecopathy, 23.6% had mastopathy, 57.1% failed to avoid secondhand smoke, less than 50% completed periodic health examinations, and 3.1% were anxious. Chronic diseases are expected to be serious health problems in the next 10 years, emphasizing the importance of women discussing their health status. Common diseases should be managed via public health service projects, and free screening and treatment of common diseases should be provided. To enhance women's health knowledge and awareness, targeted health education is necessary in accordance with their physiological and psychological characteristics.

Obesity- and lipid-related indices as a predictor of obesity metabolic syndrome in a national cohort study

Objective

Metabolic syndrome is a common condition among middle-aged and elderly people. Recent studies have reported the association between obesity- and lipid-related indices and metabolic syndrome, but whether those conditions could predict metabolic syndrome is still inconsistent in a few longitudinal studies. In our study, we aimed to predict metabolic syndrome by obesity- and lipid-related indices in middle-aged and elderly Chinese adults.

Method

A national cohort study that consisted of 3,640 adults (≥45 years) was conducted. A total of 13 obesity- and lipid-related indices, including body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), conicity index (CI), visceral adiposity index (VAI), Chinese visceral adiposity index (CVAI), lipid accumulation product (LAP), a body shape index (ABSI), body roundness index (BRI), and triglyceride glucose index (TyG-index) and its correlation index (TyG-BMI, TyG-WC, and TyG-WHtR), were recorded. Metabolic syndrome (MetS) was defined based on the criteria of the National Cholesterol Education Program Adult Treatment Panel III (2005). Participants were categorized into two groups according to the different sex. Binary logistic regression analyses were used to evaluate the associations between the 13 obesity- and lipid-related indices and MetS. Receiver operating characteristic (ROC) curve studies were used to identify the best predictor of MetS.

Results

A total of 13 obesity- and lipid-related indices were independently associated with MetS risk, even after adjustment for age, sex, educational status, marital status, current residence, history of drinking, history of smoking, taking activities, having regular exercises, and chronic diseases. The ROC analysis revealed that the 12 obesity- and lipid-related indices included in the study were able to discriminate MetS [area under the ROC curves (AUC > 0.6, P < 0.05)] and ABSI was not able to discriminate MetS [area under the ROC curves (AUC < 0.6, P > 0.05)]. The AUC of TyG-BMI was the highest in men, and that of CVAI was the highest in women. The cutoff values for men and women were 187.919 and 86.785, respectively. The AUCs of TyG-BMI, CVAI, TyG-WC, LAP, TyG-WHtR, BMI, WC, WHtR, BRI, VAI, TyG index, CI, and ABSI were 0.755, 0.752, 0.749, 0.745, 0.735, 0.732, 0.730, 0.710, 0.710, 0.674, 0.646, 0.622, and 0.537 for men, respectively. The AUCs of CVAI, LAP, TyG-WC, TyG-WHtR, TyG-BMI, WC, WHtR, BRI, BMI, VAI, TyG-index, CI, and ABSI were 0.687, 0.674, 0.674, 0.663, 0.656, 0.654, 0.645, 0.645, 0.638, 0.632, 0.607, 0.596, and 0.543 for women, respectively. The AUC value for WHtR was equal to that for BRI in predicting MetS. The AUC value for LAP was equal to that for TyG-WC in predicting MetS for women.

Conclusion

Among middle-aged and older adults, all obesity- and lipid-related indices, except ABSI, were able to predict MetS. In addition, in men, TyG-BMI is the best indicator to indicate MetS, and in women, CVAI is considered the best hand to indicate MetS. At the same time, TyG-BMI, TyG-WC, and TyG-WHtR performed better than BMI, WC, and WHtR in predicting MetS in both men and women. Therefore, the lipid-related index outperforms the obesity-related index in predicting MetS. In addition to CVAI, LAP showed a good predictive correlation, even more closely than lipid-related factors in predicting MetS in women. It is worth noting that ABSI performed poorly, was not statistically significant in either men or women, and was not predictive of MetS.

Impact of exposure to secondhand smoke on the risk of obesity in early adolescence

BACKGROUND

Exposure to secondhand smoke (SHS) might be associated with obesity in children. This study aimed to evaluate whether continuous, quit, or start exposure to SHS was associated with obesity risk in early adolescents.

METHODS

We used population-based longitudinal data of primary school students in Adachi City, Tokyo, Japan, in 2018 (4th grade) and 2020 (6th grade) and studied 3605 students. The association between continuous, quit, start, or never exposed to SHS from 4th to 6th grade and BMI categories (underweight or normal weight, overweight, obesity) in 6th grade was investigated using ordinal logistic regression models.

RESULTS

Continuous SHS group showed a higher risk of being in the high BMI category than no SHS group (OR = 1.51, 95% CI 1.16-1.96). The stratified analyses by sex showed a similar association in boys (OR = 1.74, 95% CI 1.25-2.44) but not in girls (OR = 1.14, 95% CI 0.74-1.76). Quitting SHS group did not show a higher risk of being in the high BMI category than no SHS group (OR = 1.11, 95% CI 0.75-1.66) and the same was true for boys (OR 1.46, 95% CI 0.88-2.41).

CONCLUSIONS

Continuous SHS was a risk factor for obesity in boys in early adolescence; however, quitting SHS may help prevent it.

IMPACT

Continuous secondhand smoke (SHS) was not associated with a higher risk of obesity in early adolescence in girls. Continuous SHS can be a risk factor for obesity in early adolescence in boys. Quitting SHS may help to prevent obesity in early adolescence in boys.

Reduced sleep duration increases the risk of lower urinary tract symptoms suggestive of benign prostatic hyperplasia in middle-aged and elderly males: a national cross-sectional study

BACKGROUND

The prevalence of lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH) remains high in men. However, whether reduced sleep duration enhances the risk of LUTS/BPH remains unknown.

MATERIALS AND METHODS

The 2015 China Health and Retirement Longitudinal Study was used in this study. Binary logistic regression was adopted to test the relationship between sleep duration and LUTS/BPH. Restricted cubic spline (RCS) regression was used to examine the non-linear association. In sensitivity analyses, propensity scores matching was performed to verify the robustness of the results.

RESULTS

In this study, 8,920 males aged 40 years above were enrolled. In the fully adjusted logistic model, across the quartiles of sleep duration, the odds ratios of LUTS/BPH were 1.00 (reference), 0.94 (95% CI 0.77-1.15), 0.74 (95% CI 0.58-0.94), 0.54 (0.37-0.75), respectively. The results of RCS indicated a non-linear inverted U-shaped association between sleep duration and LUTS/BPH (p for non-linearity <0.05). In the subgroup analyses, no significant effects of settlements, alcohol and cigarette consumption, depression, and hypertension on the association between sleep duration and prevalent LUTS/BPH were observed (p for interaction >0.05).

CONCLUSION

Reduced sleep duration is significantly associated with the increases of the LUTS/BPH risk in Chinese middle-aged and elderly males.

Association of environmental tobacco smoke exposure with metabolic syndrome: A longitudinal Cohort Study of 71,055 never smokers

BACKGROUND AND AIMS

Effects of environmental tobacco smoke (ETS) exposure and a change in ETS exposure status on metabolic syndrome (MetS) remain unknown. Thus, the aim of this study was to evaluate the effect of ETS exposure on MetS in self-reported and cotinine-validated never smokers.

METHODS AND RESULTS

From a large longitudinal cohort study, 71,055 cotinine-validated never smokers without MetS at baseline were included. These participants were divided into four groups (no, new, former, and continuous ETS exposure groups) based on their ETS exposure status at baseline and follow-up. The association between ETS exposure and MetS was assessed using multivariable Cox hazard regression analyses. During a median follow-up of 33 months, 15.0 cases/10,000 person-years (PY) developed MetS. Incidence rates per 10,000 PY of MetS in no, new, former, and continuous ETS exposure groups were 14.0, 18.5, 16.5, and 19.0, respectively. In multivariable Cox hazard regression analyses, the new and continuous ETS exposure groups showed increased risk of MetS compared to the no ETS exposure group (hazard ratio [95% confidence interval]: 1.35 [1.16, 1.56], p-value < 0.001 for the new ETS exposure group and 1.19 [1.06, 1.34], p-value = 0.004 for the continuous ETS exposure group). However, the former ETS exposure group did not show an increased risk of MetS (0.96 [0.88, 1.05], p-value = 0.36).

CONCLUSION

This study showed that ETS exposure and changes in ETS exposure status over approximately three years could modify the risk of MetS, suggesting that avoidance of ETS may not increase the risk of incidence of MetS.

Association between maternal shift work during pregnancy child overweight and metabolic outcomes in early childhood

Background

Previous studies found that maternal shift work during pregnancy was associated with many reproductive hazards, including small for gestational age, preterm birth, stillbirth, and neurodevelopmental impairment. Some studies also showed that these children are more likely to become overweight in early childhood. However, the association with metabolic factors, such as insulin resistance and dyslipidemia, was less studied. Hence, we aimed to understand better the relationship between maternal shift work during pregnancy and the risk of childhood overweight and metabolic outcomes. Confounding factors were also discussed, including diet, exercise, and demographical factors.

Methods

We enrolled pregnant women before delivery in the Taiwan Birth Panel Study (TBPS) II conducted between 2010 and 2012, and followed the children of these participants in 2018. The objective of this study is to investigate the influence of prenatal and postnatal factors on infant and early childhood health. During the follow-up in 2018, we checked children's demographic data, obtained blood specimens, and checked their blood sugar, blood insulin, and lipid profiles. Structured questionnaires were used to evaluate demographic data. Multiple linear and logistic regressions were used to examine the associations between maternal shift work during pregnancy and child overweight, metabolic disorders, such as HOMA-IR, and lipid profiles.

Results

In this study, we included 407 mother-children pairs with different work shifts (350 day workers and 57 shift workers), and a sub-population without underweight children was also created (290 day workers and 47 shift workers). Shift work during pregnancy was associated with a higher Homeostasis Model Assessment-Insulin Resistance index (HOMA-IR) and a higher odds ratio for overweight in children born from mothers doing shift work during pregnancy after adjustment. The findings were attenuated when we investigated the effect of shift work before pregnancy.

Conclusion

Our study suggested that maternal shift work during pregnancy was associated with child overweight and insulin resistance in early childhood.

Explore the Relationship Between Short-Term Ambient Air Pollution Exposure and Daily Outpatient Visits for Metabolic Related Fatty Liver

Background

Many studies have shown that the pollution of fine particles in the air is related to the incidence of chronic diseases. However, research on air pollution and metabolism-associated fatty liver disease (MAFLD) is limited.

Objective

The purpose of this study was to explore the relationship between short-term ambient air pollution and daily outpatient visits for metabolic-related fatty liver.

Methods

We used a quasi-Poisson regression generalized additive model to stratify analyses by season, age, and gender.

Results

From January 1, 2017, to August 31, 2019, 10,562 confirmed MAFLD outpatient visits were recorded. A 10 µg/m³ increase of fine particular matter (PM10and PM2.5) and NO₂ concentrations corresponding with percent change were 0.82 (95% confidence interval [CI], 0.49–1.15), 0.57 (95% CI, 0.18–0.98), and 0.86 (95% CI, 0.59–1.13) elevation in MAFLD outpatient visits. In terms of season, the impact estimates of NO₂ and PM2.5% change were 3.55 (95% CI, 1.23–5.87) and 1.12 (95% CI, 0.78–1.46) in the hot season and transition season, respectively. Compared with the warm season, the impact estimates of PM10were more significant in the cool season: 2.88 (95% CI, 0.66–5.10). NO₂ has the greatest effect in the transition season, whereas PM10 has the greatest highest effect in the cool and hot seasons. Compared with other pollutants, PM2.5 has the greatest impact in the age stratification, which percent change are 2.69 (95% CI, 0.77–5.61) and 2.88 (95% CI, 0.37–6.40) respectively. The impact values of PM2.5 in male and female percent change were 3.60 (95% CI, 0.63–6.57) and 1.65 (95% CI, 1.05–2.25), respectively.

Conclusion

This study shows that the air pollutants are related to the number of outpatient visits for MAFLD. The effects of different air pollutants on MAFLD outpatient visits were different by season, ages, and gender.

Obesity II: Establishing causal links between chemical exposures and obesity

Obesity is a multifactorial disease with both genetic and environmental components. The prevailing view is that obesity results from an imbalance between energy intake and expenditure caused by overeating and insufficient exercise. We describe another environmental element that can alter the balance between energy intake and energy expenditure: obesogens. Obesogens are a subset of environmental chemicals that act as endocrine disruptors affecting metabolic endpoints. The obesogen hypothesis posits that exposure to endocrine disruptors and other chemicals can alter the development and function of the adipose tissue, liver, pancreas, gastrointestinal tract, and brain, thus changing the set point for control of metabolism. Obesogens can determine how much food is needed to maintain homeostasis and thereby increase the susceptibility to obesity. The most sensitive time for obesogen action is in utero and early childhood, in part via epigenetic programming that can be transmitted to future generations. This review explores the evidence supporting the obesogen hypothesis and highlights knowledge gaps that have prevented widespread acceptance as a contributor to the obesity pandemic. Critically, the obesogen hypothesis changes the narrative from curing obesity to preventing obesity.

Effect of Exposure to Paternal Smoking on Overweight and Obesity in Children: Findings from the Children Lifeway Cohort in Shenzhen, Southern China

INTRODUCTION

Paternal smoking associated with childhood overweight and obesity has been a concern, but studies have not investigated smoking exposure and smoking details. We investigated the association of exposures from paternal smoking as well as smoking details on offspring overweight/obesity.

METHODS

A total of 4,513 children (aged 7-8 years) in Shenzhen were enrolled. Four different exposures from paternal smoking as well as smoking quantity, duration of smoking, and age of starting smoking details were the exposure variables and demographic characteristics, and circumstances of birth, dietary intake, lifestyle, and nonpaternal-smoking exposure were covariates in the logistic regression analysis to determine the effect of paternal smoking on childhood overweight/obesity, estimating odds ratios (ORs), and 95% confidence intervals (CIs).

RESULTS

Paternal smoking was positively associated with childhood overweight/obesity (p < 0.05). Moreover, only preconception exposure, and both pre- and postconception exposure were significantly associated with childhood overweight/obesity (OR 1.54 [95% CI: 1.14-2.08] and OR 1.73 [95% CI: 1.14-2.61], respectively), restricted to boys but not girls. Furthermore, for children with only preconception paternal-smoking exposure, the dose-response relation was positive between smoking quantity, duration of smoking, age at starting, and overweight/obesity for boy offspring (p trend <0.001). We did not find any significant association between only postnatal exposure to paternal smoking and childhood overweight/obesity (p > 0.05).

CONCLUSIONS

Our findings suggest that paternal smoking is associated with boys' overweight/obesity, and this association may be due to the paternal-smoking exposure before conception rather than the postnatal exposure to paternal smoking. Reducing paternal-smoking exposure before conception might help reduce overweight/obesity in boys.

Cannabis use and metabolic syndrome among clients with first episode psychosis

AIM

To explore the relationship between cannabis use and metabolic syndrome (MetS) among those who have experienced first episode psychosis (FEP).

METHODS

A retrospective analysis of 404 participants enrolled in the Recovery After Initial Schizophrenia Episode-Early Treatment Program (RAISE-ETP) was conducted. Using multiple logistic regression, we investigated the correlation between cannabis use and rate of MetS at baseline and across time as well as the specific metabolic derangements among cannabis users and abstainers.

RESULTS

Although cannabis users had similar rates of MetS at baseline when compared with abstainers, those who used cannabis at any time during the study period tended to have lower triglycerides and elevated high-density lipoprotein (HDL). Cannabis users were less likely to develop MetS, relative to nonusers.

CONCLUSIONS

Cannabis use may be associated with lower incidence of MetS in patients who have experienced FEP. Further research is indicated to develop these observations.

Relationship between childhood secondhand smoke exposure and the occurrence of hyperlipidaemia and coronary heart disease among Chinese non-smoking women: a cross-sectional study

OBJECTIVE

The objective of this study was to evaluate the influence of secondhand smoke (SHS) exposure during childhood on type 2 diabetes mellitus, hypertension, hyperlipidaemia and coronary heart disease among Chinese non-smoking women.

METHODS

In this cross-sectional study, the SHS exposure data in childhood were obtained using a questionnaire survey. Self-reported childhood SHS exposure was defined as the presence of at least one parent who smoked during childhood.

RESULTS

Of the 6522 eligible participants, 2120 Chinese women who had never smoked were assessed. The prevalence of SHS exposure in the entire population was 28.1% (596). SHS exposure during childhood was not significant for the standard risk factors of type 2 diabetes mellitus (p=0.628) and hypertension (p=0.691). However, SHS was positively associated with hyperlipidaemia (p=0.037) after adjusting for age, obesity, education status, physical activity, alcohol consumption, current SHS exposure status, diabetes mellitus and hypertension. In addition, childhood SHS increased the occurrence of coronary heart disease (p=0.045) among non-smokers after further adjusting for hyperlipidaemia.

CONCLUSION

SHS exposure during childhood is associated with prevalent hyperlipidaemia and coronary heart disease in adulthood among non-smoking Chinese women.

The Association of Passive Smoking and Dyslipidemia Among Adolescence in Japan: Results From A-CHILD Study

CONTEXT

Passive smoking in childhood has been reported to be associated with dyslipidemia in Western countries. However, this association in Asian countries remains unclear. Further, no study has investigated the sex difference of the association.

OBJECTIVE

This study aimed to elucidate the association between passive smoking and dyslipidemia in adolescent boys and girls in Japan.

METHODS

We used a cross-sectional data of junior high school students in the Adachi Child Health Impact of Living Difficulty (A-CHILD) study in Adachi City, Tokyo, Japan in 2016 and 2018. Of the 1431 available students, 1166 students and their parents responded to the survey, including frequency of passive smoking (response rate 81.5%). We assessed dyslipidemia using total cholesterol (TC) levels, low-density lipoprotein cholesterol (LDL-C) levels and high-density lipoprotein cholesterol (HDL-C) levels. The association between passive smoking and dyslipidemia was evaluated by using multivariate regression analyses adjusted for socioeconomic status and lifestyle factors stratified by boys (N = 564) and girls (N = 602).

RESULTS

Among boys, HDL-C levels were significantly lower if exposed to passive smoking frequently, compared with those not exposed (β = -3.19; 95% CI, -5.84 to -0.55). However, this trend does not hold true among girls. Passive smoking was not associated with TC levels and LDL-C levels in either boys or girls.

CONCLUSION

We found that exposure to passive smoking was associated with HDL-C level among boys in Japan, but not in girls. Further longitudinal study is needed to confirm the association between passive smoking and dyslipidemia among boys in Japan.

Sex-specific clustering of metabolic risk factors and cancer risk: a longitudinal study in Iran

Background

Cancer is a major cause of death in low- and middle-income countries. A large number of studies have shown that some of the metabolic risk factors (MRFs) tend to cluster in individuals. We examined the synergistic effects of multiple MRFs and cancer risk among Iranian adults.

Methods

Among 8593 (3929 men) participants aged ≥ 30 years, the self-organizing map (SOM) was applied to clustering of four MRFs including high fasting plasma glucose (HFPG), high total cholesterol (HTC), high systolic blood pressure (HSBP), and high body mass index (HBMI). The Cox proportional hazards model was used to investigate the association between clusters with cancer incidence during a median of 14.0 years of follow-up.

Results

During the study period, 265 new cases of cancer were identified among participants at risk. The incidence density rate was 2.5 per 1000 person years in total population. About 32 and 40% of men and women, respectively, had three or four MRFs. We identified seven clusters of MRFs in both men and women. In both genders, MRFs were clustered in those with older age. Further, inverse associations were found between current smoking in men, and education level and passive smoking in women and clustering of MRFs. In men, a cluster with 100% HSBP and HBMI had the highest risk for overall cancer. While, among women, a cluster with 100% HFPG and 93% HBMI yielded the highest risk for cancer. The risk was decreased when HBMI accompanied by HTC.

Conclusions

Clustering patterns may reflect underlying link between MRFs and cancer and could potentially facilitate tailored health promotion interventions.