The association between physical activities combined with dietary habits and cardiovascular risk factors

Objectives

The aim of this study was to investigate the association between physical activities combined with dietary habits and cardiovascular risk factors in adults from Nanjing, China.

Methods

The cross-sectional survey conducted in 2017 involved a sample of 60 283 individuals aged ≥18 years in Nanjing municipality, China. The sampling method used was multistage stratified cluster sampling. The primary outcomes from multivariate logistic regression analysis with adjusted potential confounders were the relationships between physical activities combined with dietary habits and cardiovascular risk variables. Relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (S) were used to assess an additive interaction between dietary habits and physical activities.

Results

After adjusting potential confounders, cardiovascular risk factors were significantly associated with the association of physical inactivity and unhealthy diet, with the highest odds ratios (ORs) for low density lipoprotein-cholesterol (HLDL-c) (1.64, 95% CI [1.47, 1.84]) and hypertension (1.55, 95% CI [1.46, 1.64]). Additive interactions between physical inactivity and unhealthy diet were found in on cardiovascular risk factors of higher low-density lipoprotein-cholesterol (HLDL-c) (S, 2.57; 95% CI [1.27, 5.21]), type 2 diabetes (T2D) (S, 1.96; 95% CI [1.23, 3.13]), dyslipidemia (S, 1.69; 95% CI [1.08, 2.66]) and hypertension (S, 1.46; 95% CI [1.12, 1.89]). Their RERI was 0.39 (95% CI [0.18, 0.60]), 0.22 (95% CI [0.09, 0.35]), 0.11 (95% CI [0.03, 0.19]) and 0.17 (95% CI [0.06, 0.28]), respectively. OR of being HLDL-c, T2D, hypertension and dyslipidemia in participants of physical inactivity and unhealthy diet was 24%, 15%, 11% and 8.3%, respectively. Multiplicative interaction was detected in obesity, hypertension, T2D and HLDL-c.

Conclusion

An unhealthy diet and physical inactivity were strongly linked to cardiovascular risk factors. This study also showed that an unhealthy diet and physical inactivity combined to produce an additive effect on T2D, hypertension, HLDL-c, and dyslipidemia, suggesting a higher risk than the total of these factors, especially HLDL-c. Preventive strategies aimed at reducing cardiometabolic risks such as hypertension, T2D, HLDL-c, and dyslipidemia are necessary for targeting physical inactivity and unhealthy diet.

Additive interaction of family medical history of diabetes with hypertension on the diagnosis of diabetes among older adults in India: longitudinal ageing study in India

BACKGROUND

The present study aimed to estimate the additive interaction of family history of diabetes and hypertension on the diagnosis of diabetes among individuals aged 45 years and above in India. The coexistence of these two exposures may act synergistically on the risk of diabetes, leading to adverse health outcomes.

METHODS

The study utilized the data from the Longitudinal Ageing Study in India (LASI) Wave 1 (2017-2018). The total sample size for the current study was 58,612 individuals aged 45 years and above. Multivariable logistic regression models were employed to determine the individual and joint effect of a family history of diabetes with hypertension on diabetes. An additive model was applied to assess the interaction effect of the family medical history of diabetes with hypertension on the diagnosis of diabetes by calculating three different measures of additive interaction such as the relative excess risk ratio (RERI), attribution proportion due to interaction (AP), and synergy index (S).

RESULTS

The prevalence of diabetes was three times higher among individuals with family history of diabetes (27.8% vs. 9.2%) than those without family history. Individuals with family history of diabetes (AOR: 2.47, CI: 2.11 2.89) had 2.47 times higher odds of having diabetes than those without family history. The prevalence of diabetes was significantly higher among individuals with hypertension and family history of diabetes (46.6%, 95% CI: 39.7-53.6) than those without the coexistence of family history of diabetes and hypertension (9.9%, 95% CI: 9.5-10.4), individuals with hypertension and without a family history of diabetes (22.7%, 95% CI: 21.2-24.2), and individuals with family history of diabetes and without hypertension (16.5%, 95% CI: 14.5-18.7). Moreover, the adjusted odds ratio (AOR) of the joint effect between family medical history of diabetes and hypertension on diabetes was 9.28 (95% CI: 7.51-11.46). In the adjusted model, the RERI, AP, and S for diabetes were 3.5 (95% CI: 1.52-5.47), 37% (0.37; 95% CI: 0.22-0.51), and 1.69 (95% CI: 1.31-2.18) respectively, which indicates that there is a significant positive interaction between family history of diabetes and hypertension on the diagnosis of diabetes. The study findings on interaction effects further demonstrate consistent results for two models of hypertension (self-reported hypertension and hypertensive individuals receiving medication) even after adjustment with potential confounding factors on diabetes (self-reported diabetes and individuals with diabetes receiving medication).

CONCLUSIONS

The study findings strongly suggest that the interaction of family history of diabetes with hypertension has a positive and significant effect on the risk of diabetes even after adjustment with potential confounding factors. Furthermore, the findings indicate a synergistic effect, emphasizing the importance of considering both family medical history of diabetes and hypertension when assessing diabetes risk and designing preventive strategies or interventions.

Associations of evening-type and insomnia symptoms with depressive symptoms among youths

BACKGROUND

Evening-type and insomnia symptoms are significantly related to each other and independently associated with depressive symptoms, yet few studies have examined the potential interaction between these two conditions. Therefore, we aimed to examine the associations of evening-type and insomnia symptoms with depressive symptoms among Chinese youths, with a specific focus on the joint effects of the two conditions on depressive symptoms.

METHODS

Participants aged between 12 and 25 were invited to participate in an online survey from December 15, 2022, to May 26, 2023. Multivariate logistic regression models and additive interaction models were used to examine the independent and joint effects of chronotypes and insomnia symptoms on depressive symptoms, respectively.

RESULTS

Of the 6145 eligible youths, the prevalence of evening-type and insomnia symptoms were 24.9 % and 29.6 %, respectively. Both evening-type (adjusted OR, [AdjOR]: 3.21, 95 % CI: 2.80-3.67) and insomnia symptoms (AdjOR: 10.53, 95 % CI: 9.14-12.12) were associated with an increased risk of depressive symptoms. In addition, the additive interaction models showed that there is an enhanced risk of depression related to interaction between evening-type and insomnia symptoms (relative excess risk due to interaction, [RERI]: 11.66, 95 % CI: 7.21-16.11).

CONCLUSIONS

The present study provided additional evidence demonstrating the presence of interaction between evening-type and insomnia symptoms, which can lead to a higher risk of depressive symptoms. Our findings argue the need for addressing both sleep and circadian factors in the management of depressive symptoms in young people.

Combined association of abdominal obesity and depressive symptoms with risk of type 2 diabetes: A cohort study

OBJECTIVE

To explore the combined effect of abdominal obesity and depressive symptoms on the risk to type 2 diabetes, while also assessing the potential influence of various glycemic states and gender on this combined relationship.

METHODS

Data is acquired from the China Health and Retirement Longitudinal Study, and 5949 participants were included for analysis. Participants were divided into four groups: neither have abdominal obesity nor depressive symptoms (AO-/DS-), only have depressive symptoms (AO-/DS+), only have abdominal obesity (AO+/DS-), and have both abdominal obesity and depressive symptoms (AO+/DS+). Stratified analyses differentiating the glycemic statuses and sex of the participants were also carried out.

RESULTS

After adjusting for the confounders, the AO-/DS+, AO+/DS- and AO+/DS+ phenotypes were all discovered to be risk factors for type 2 diabetes (OR = 1.38, 95%CI: 1.06-1.79; OR = 2.07, 95%CI: 1.63-2.63; OR = 2.38, 95%CI: 1.83-3.11, respectively) compared with the AO-/DS- phenotype in the overall population. In further stratified analyses, we arrived at the same conclusion for normoglycemic individuals, especially in females. For prediabetes and males, the AO+/DS- and AO+/DS+ phenotypes are risk factors for type 2 diabetes compared with the AO-/DS- phenotype, but not with AO-/DS+.

CONCLUSION

Regardless of glycemic status and sex, the coexistence of abdominal obesity and depressive symptoms were associated with an increased risk of type 2 diabetes. Depressive symptoms were independent risk factors for type 2 diabetes only in normoglycemic individuals and females.

Association of cognitive reserve with the risk of dementia in the UK Biobank: role of polygenic factors

BACKGROUND

It remains unclear whether cognitive reserve can attenuate dementia risk among people with different genetic predispositions.

AIMS

We aimed to examine the association between cognitive reserve and dementia, and further to explore whether and to what extent cognitive reserve may modify the risk effect of genetic factors on dementia.

METHOD

Within the UK Biobank, 210 631 dementia-free participants aged ≥60 years were followed to detect incident dementia. Dementia was ascertained through medical and death records. A composite cognitive reserve indicator encompassing education, occupation and multiple cognitively loaded activities was created using latent class analysis, categorised as low, moderate and high level. Polygenic risk scores for Alzheimer's disease were constructed to evaluate genetic risk for dementia, categorised by tertiles (high, moderate and low). Data were analysed using Cox models and Laplace regression.

RESULTS

In multi-adjusted Cox models, the hazard ratio (HR) of dementia was 0.66 (95% confidence interval (CI) 0.61-0.70) for high cognitive reserve compared with low cognitive reserve. In Laplace regression, participants with high cognitive reserve developed dementia 1.62 (95% CI 1.35-1.88) years later than those with low cognitive reserve. In stratified analysis by genetic risk, high cognitive reserve was related to more than 30% lower dementia risk compared with low cognitive reserve in each stratum. There was an additive interaction between low cognitive reserve and high genetic risk on dementia (attributable proportion 0.24, 95% CI 0.17-0.31).

CONCLUSIONS

High cognitive reserve is associated with reduced risk of dementia and may delay dementia onset. Genetic risk for dementia may be mitigated by high cognitive reserve. Our findings underscore the importance of enhancing cognitive reserve in dementia prevention.

The comparison of mortality burden between exposure to dry-cold events and wet-cold events: A nationwide study in China

BACKGROUND

Most previous studies have focused on the health effect of temperature or humidity, and few studies have explored the combined health effects of exposure to temperature and humidity. This study aims to estimate the relationship between humidity-cold events and mortality, and then to compare the mortality burden between exposure to dry-cold events and wet-cold events, and finally to explore whether there was an additive interaction of temperature and humidity on mortality.

METHODS

In the study, Daily mortality data during 2006-2017 were collected from Centers for Disease Control and Prevention in China, and daily mean temperature and daily mean relative humidity data from 698 weather stations in China were obtained from the China Meteorological Data Sharing Service system. We first employed time-series design with a distributed lag nonlinear model and a multivariate meta-analysis model to examine the association between humidity-cold events with mortality.

RESULTS

We found that humidity-cold events significantly increased mortality risk, and the effect of wet-cold events (RR:1.24, 95%CI:1.20,1.29) was higher than that of dry-cold events (RR:1.14, 95%CI:1.10,1.18). Dry-cold events and wet-cold events accounted for 2.41 % and 2.99 % excess deaths, respectively with higher burden for the elderly ≥85 years old, Central China and CVD. In addition, there is a synergistic additive interaction between low temperature and high humidity in winter.

CONCLUSION

This study showed that humidity-cold events significantly increased mortality risk, and the effect of wet-cold events was higher than that of dry-cold events.

The joint association of ambient air pollution and different sleep posture with mild obstructive sleep apnea: A study conducted at Taipei Sleep Center

BACKGROUND

Growing evidence suggests the detrimental impact of supine position and air pollution on obstructive sleep apnea (OSA), as well as the potential benefits of nonsupine positions. However, their interaction effects on OSA remain unclear.

OBJECTIVES

To evaluate the interaction effects of air pollution (NO2/PM2.5) and sleep position on OSA on additive and multiplicative scales.

METHODS

This study included 3330 individuals. Personal exposure to air pollution was assessed using a spatiotemporal model. OSA was diagnosed through polysomnography. The associations of supine and nonsupine positions and air pollutants with mild-OSA and their interaction effects on mild-OSA. were explored through generalized logistic regression.

RESULTS

Supine position and high NO2 level independently increased the risk of mild-OSA, while PM2.5 was not associated with mild-OSA. Significant interactions were observed between supine position and NO2 at different lag periods (0-7 days, 0-1 year, and 0-2 years) (P = 0.042, 0.013, and 0.010, respectively). The relative excess risks due to interactions on the additive scale for 1-week, 1-year, and 2-year NO2 exposure and supine position were 0.63 (95 % CI: 0.10-1.16), 0.56 (95 % CI: 0.13-0.99), and 0.64 (95 % CI: 0.18-1.10); the corresponding odds ratios for interactions on the multiplicative scale were 1.45 (95 % CI: 1.01-2.07), 1.55 (95 % CI: 1.09-2.22), and 1.60 (95 % CI: 1.12-2.28). The positive interactions persisted in men and participants with obesity. No interaction was observed between nonsupine position and NO2 levels; nevertheless, significant interactions were noted on both the negative additive and multiplicative scales in men.

CONCLUSION

Prolonged supine sleep significantly increased the risk of mild-OSA, particularly in men and individuals with obesity. Although the benefits of nonsupine position are considerably less than the risks of NO2 exposure, avoiding prolonged supine sleep may reduce the risk of mild-OSA caused by high levels of NO2 in men.

Sulfur-containing amino acids and risk of schizophrenia

BACKGROUND

Schizophrenia is a chronic and complex severe psychiatric disorder. Male and female are different in their risks for schizophrenia for the biologic and sociocultural reasons. Homocysteine (Hcy), Cysteine (Cys), and methionine (Met) play important roles in metabolism, and the three amino acids may also be involved in pathogenesis of schizophrenia.

OBJECTIVE

This study aimed to test the associations between sulfur-containing amino acid blood levels and risk of schizophrenia, evaluating the different risk in male and female.

METHODS

We organized a case-control study on 876 individuals with schizophrenia and 913 age- and sex-matched healthy subjects as control group. The concentrations of Hcy, Cys and Met were measured by liquid chromatography-tandem mass spectrometry technology. Subsequently, restricted cubic spline was applied to explore full-range associations of these amino acids with schizophrenia. Interactions between levels of the three amino acids and sex on additive scale were also tested.

RESULTS

Hcy levels at ≤29 μmol/L were associated with sharply increased risk of schizophrenia, inversely, Met was associated with sharply decreased risk of schizophrenia at levels ≤22 μmol/L. Increased Cys levels were associated with decreased risk of schizophrenia. Almost inverse associations were observed between Cys/Hcy and Met/Hcy ratios and schizophrenia. Significant synergistic interactions between levels of all the three amino acids and sex were discovered on an additive scale.

CONCLUSIONS

Our study suggests a close association between sulfur-containing amino acids and schizophrenia with different risk in male and female. Future studies are demanded to clarify the pathogenic role of Hcy, Cys and Met in schizophrenia.

Familial Risk and Interaction With Smoking and Alcohol Consumption in Bladder Cancer: A Population-Based Cohort Study

Background

Although genetic factors are known to play a role in the pathogenesis of bladder cancer, population-level familial risk estimates are scarce. We aimed to quantify the familial risk of bladder cancer and analyze interactions between family history and smoking or alcohol consumption.

Methods

Using the National Health Insurance database, we constructed a cohort of 5,524,403 study subjects with first-degree relatives (FDRs) and their lifestyle risk factors from 2002 to 2019. Familial risk was calculated using hazard ratios (HRs) with 95% confidence intervals (CIs) that compare the risk of individuals with and without affected FDRs. Interactions between family history and smoking or alcohol intake were assessed on an additive scale using the relative excess risk due to interaction (RERI).

Results

Offspring with an affected parent had a 2.09-fold (95% CI: 1.41 - 3.08) increased risk of disease compared to those with unaffected parents. Familial risks of those with affected father and mother were 2.26 (95% CI: 1.51 - 3.39) and 1.10 (95% CI: 0.27 - 4.41), respectively. When adjusted for lifestyle factors, HR reduced slightly to 2.04 (95% CI: 1.38 - 3.01), suggesting that a genetic predisposition is the main driver in the familial aggregation. Smokers with a positive family history had a markedly increased risk of disease (HR: 3.60, 95% CI: 2.27 - 5.71), which exceeded the sum of their individual risks, with statistically significant interaction (RERI: 0.72, 95% CI: 0.31 - 1.13). For alcohol consumption, drinkers with a positive family history also had an increased risk of disease, although the interaction was not statistically significant (RERI: 0.05, 95% CI: -3.39 - 3.48).

Conclusion

Smokers and alcohol consumers with a positive family history of bladder cancer should be considered a high-risk group and be advised to undergo genetic counseling.

Associations of socioeconomic status and obesity with hypertension in tibetan adults in a Chinese plateau area

BACKGROUND

Previous studies have identified that socioeconomic status (SES) and obesity are associated with hypertension. However, their interaction on hypertension risk has not yet been assessed.

METHODS

The study used data from 6,069 Tibetan residents in Chengguan District in Lhasa, the Chinese Tibetan autonomous region's capital, based on a cohort study conducted from May 2018 to September 2019 in five provinces in southwest China. We used logistic regression models to assess the complex relations of SES and obesity with hypertension.

RESULTS

Compared with individuals of high SES, low and moderate SES were positively associated with high risk of hypertension. SES and obesity have significant additive interaction on hypertension (general obesity by BMI: RERI = 1.33, P < 0.001; abdominal obesity by WC: RERI = 0.76, P < 0.001; abdominal obesity by WHtR: RERI = 0.96, P < 0.001). In people from the low and moderate SES segments, obesity was linked to an increased risk of hypertension, but the correlations were stronger in people from the moderate SES category. Compared with people of high SES and non obese, those with moderate SES and obesity had a higher risk of hypertension, and ORs were 4.38 (2.80, 6.84) for general obesity by BMI, 3.38 (2.05, 5.57) for abdominal obesity by WC, and 3.18 (1.57, 6.42) for abdominal obesity by WHtR.

CONCLUSION

There is an independent and additive interaction effect of obesity and SES on the risk of hypertension. People with obesity, especially those of moderate and low SES, should reduce weight and waist circumference, and pay more attention to blood pressure. Moreover, the government, health administration departments, and society should prioritize improving the socioeconomic status of the Tibetan population and addressing risk factors like obesity.

Circulating hyaluronidase in early pregnancy and increased risk of gestational diabetes in Chinese pregnant women: A nested case control study

BACKGROUND AND AIMS

To explore association of serum hyaluronidase 1 (HYAL1) level in early pregnancy with gestational diabetes mellitus (GDM), and to examine interactive effects of HYAL1 with ceramides species on GDM risk.

MATERIALS AND METHODS

We conducted a 1:1 matched case-control study (n = 414) of pregnant women from 2010 to 2012 in Tianjin, China. Blood samples were collected at the first antenatal care visit (at a median of 10th gestational weeks). Binary conditional logistic regression and restricted cubic spline (RCS) analysis were used to examine full-range risk association between HYAL1 and GDM. Additive interactions and multiplicative interactions were employed to test interactive effects of HYAL1 with ceramides species on GDM risk.

RESULTS

Ln HYAL1 was linearly associated with GDM risk and the adjusted OR of HYAL1 ≥ vs. < its median for GDM was significant (1.65, 95%CI: 1.08-2.52). High HYAL1 markedly enhanced the ORs of high ceramide 18:0 for GDM from 2.31 (1.06-5.01) to 6.74 (2.85-16.0), and low ceramide 24:0 from 3.08 (1.33-7.11) to 8.15 (3.03-21.9), with significant additive interactions.

CONCLUSIONS

High HYAL1 in early pregnancy may increase the risk of GDM in Chinese women, possibly via enhancing the effects of high ceramide 18:0 and low ceramide 24:0 on GDM risk.

Associations of social jetlag and insomnia symptoms with depressive symptoms among Chinese adolescents: A large population-based study

OBJECTIVE

This study aimed to evaluate the associations of social jetlag and insomnia symptoms with depressive symptoms among adolescents.

METHODS

A total of 37,871 junior high students completed an online survey between May 24th and Jun 5th, 2022. Insomnia symptoms were assessed by three items based on the Diagnostic and Statistical Manual of Mental Disorders criteria. Social jetlag and depressive symptoms were evaluated by the Munich Chronotype Questionnaire and the Patient Health Questionnaire, respectively. Restricted cubic splines were used to explore the relationship between social jetlag and depressive symptoms. Joint effects of social jetlag and insomnia symptoms on depressive symptoms were estimated using additive interaction models.

RESULTS

The prevalence of depressive symptoms was 13.1%. Depressive symptoms were more common in adolescents with social jetlag ≥2 h (OR: 1.51, 95% CI: 1.39-1.65) and insomnia symptoms (OR: 6.91, 95% CI: 6.41-7.44). There was a J-shaped relationship between social jetlag and depressive symptoms when we took social jetlag as a continuous variable. Moreover, a positive additive interaction of social jetlag ≥2 h and insomnia symptoms on depressive symptoms was found in female adolescents (RERI: 2.30, 95% CI: 0.11-4.49).

CONCLUSIONS

Our findings suggested that social jetlag ≥2 h and insomnia are related to the occurrence of depressive symptoms in adolescents. Their coexistence additively enhances the strength of the association with depressive symptoms. Early screening and intervention for insomnia, as well as methods to reduce social jetlag, should be comprised as part of preventive strategies for depression in adolescents.

Association of air pollutants and osteoporosis risk: The modifying effect of genetic predisposition

BACKGROUND

Limited studies have examined the association between air pollutants and osteoporosis incidence; however, the results are conflicting. We aimed to quantify the effects of selected air pollutants on osteoporosis risk and explore the modifying effect of genetic predisposition.

METHODS

A total of 422,955 subjects who did not have osteoporosis at baseline in the UK Biobank were included from 2006 to 2010. We conducted a Cox proportional hazards model with adjustment for covariates to examine the association between air pollutant scores and individual air pollutants and incident osteoporosis. Furthermore, a polygenic risk score (PRS) of osteoporosis was built and examined to determine whether genetic susceptibility modified the effect of air pollutants on osteoporosis. The relationship between air pollutants and osteoporosis was examined by using a restricted cubic spline (RCS) method.

RESULTS

After confounder adjustment, the results showed a remarkable increase in the risk of osteoporosis with each 10 unit increase in exposure to air pollution (hazard ratio: 1.06, 95 % confidence interval: 1.03-1.08), PM_2.5 (1.94, 1.52-2.48), NO₂ (1.06, 1.02-1.10), and NO_X (1.03, 1.01-1.04). However, no significant association was observed between PM₁₀ or PM_2.5-10 exposure and osteoporosis. Subjects with high air pollutant exposure levels and a high PRS had a noteworthy increase in osteoporosis risk compared to those with low air pollutant exposure levels and a low PRS. Air pollutants and genetic variants exerted additive effects on the risk of osteoporosis. Positive correlations were observed between osteoporosis and PM_2.5 (P < 0.001), NO₂ (P = 0.001), and NOx (P = 0.002) exposure.

CONCLUSIONS

Exposure to PM_2.5, NO₂ and NOx was associated with an increase in osteoporosis risk, and this effect was more pronounced in populations with high genetic risk. The association between PM_2.5, NO₂ and NOx exposure and osteoporosis is modified by genetic variations.

Independent and combined associations of depressive symptoms and sleep disturbance with chronic pain in community-dwelling older adults

Supplemental Digital Content is Available in the Text.

The combination of depressive symptoms and sleep disturbance was positively associated with chronic pain, but there were no additive interactions in community-dwelling older adults.

Introduction:

There is limited evidence regarding whether depressive symptoms and sleep disturbance are independently or synergistically associated with chronic pain.

Objectives:

We investigated the independent and combined associations of depressive symptoms and sleep disturbance with chronic pain and its severity (and the additive interactions) in community-dwelling older adults.

Methods:

This cross-sectional study analyzed the data of 1374 individuals who were 65 to 75 year old, not in need of long-term care, and completed questionnaires assessing sociodemographic factors, depressive symptoms, sleep disturbance, and chronic pain. The severity of chronic pain was assessed based on pain intensity, pain distribution, and pain type. The participants' status of depressive symptoms and sleep disturbance were categorized in the following 4 groups: neither condition, depressive symptoms alone, sleep disturbance alone, and both conditions.

Results:

Among the 1374 participants, 849 (61.8%) had chronic pain. The multivariable-adjusted odds ratios and 95% confidence intervals of the presence of chronic pain in those with depressive symptoms alone, sleep disturbance alone, and both conditions were 1.40 (0.97–2.03), 1.98 (1.41–2.78), and 2.12 (1.39–2.23), respectively, compared with the neither-condition group. Similar associations were observed for severe chronic pain. However, there were no significant additive interactions. In addition, only sleep disturbance was significantly associated with chronic pain, after adjusting for depressive symptoms.

Conclusions:

Our analyses did not reveal a synergistic effect of depressive symptoms and sleep disturbance on chronic pain and its severity, suggesting that most of the effects of depressive symptoms on chronic pain may be mediated by sleep disturbance.

Population attributable fraction of lung cancer due to genetic variants, modifiable risk factors, and their interactions: a nationwide prospective cohort study

BACKGROUND

Genetic variants and modifiable risk factors (including environmental exposure and lifestyle) greatly contribute to the development of lung cancer. The population attributable fraction (PAF) of these risk factors, especially their interactive effects, has not been well quantified.

METHODS

A total of 398,577 participants were included in this analysis. There were 2504 incident lung cancer cases identified over an average 10.4-year follow-up. We applied Cox proportional hazards models to examine the associations between risk factors and incident lung cancer. We further developed a polygenic risk score and evaluated whether environmental factors modified the effect of genetic risk on incident lung cancer. Furthermore, we calculated the PAF for each risk factor, as well as their gene-environment additive interaction, and then combined them to create a weighted PAF that takes into consideration participants with overlapping risk factors.

RESULTS

Our analysis showed that smoking was the leading risk factor for lung cancer with a PAF of 63.73%. We observed additive interactions between smoking, PM_2.5, NO_x, and genetic risk, with PAFs of 17.85% (smoking-high genetic risk interaction), 10.79% (smoking-intermediate genetic risk interaction), 5.30% (NO_x-high genetic risk interaction), 6.55% (PM_2.5-high genetic risk interaction), and 4.99% (PM_2.5-intermediate genetic risk interaction). We estimated that 73.46% of lung cancer cases could be attributable to potentially modifiable risk factors after adjusting for the correlation between them.

CONCLUSION

High genetic risk and several modifiable factors may increase the risk of incident lung cancer. Participants with a high genetic risk may be more vulnerable to developing lung cancer if exposed to smoking and/or high air pollution. Our findings provide evidence that the majority of incident lung cancer cases could be prevented by eliminating modifiable risk factors.

Associations of genetic risk factors and air pollution with incident hypertension among participants in the UK Biobank study

The purposes of this study were to quantify the association of the combination of air pollution and genetic risk factors with hypertension and explore the interactions between air pollution and genetic risk. This study included 391,366 participants of European ancestry initially free from pre-existing hypertension in the UK Biobank. Exposure to ambient air pollutants, including particulate matter (PM_2.5 PM_2.5-10, and PM₁₀), nitrogen dioxide (NO₂) and nitrogen oxides (NO_X), was estimated through land use regression modelling, and the associations between air pollutants and the incidence of hypertension were investigated using a Cox proportional hazards model adjusted for covariates. Furthermore, we established a polygenic risk score for hypertension and assessed the combined effect of genetic susceptibility and air pollution on incident hypertension. The results showed significant associations between the risk of hypertension and exposure to PM_2.5 (hazard ratio [HR]: 1.41, 95% confidence interval [CI]: 1.29-1.53; per 10 μg/m³), PM₁₀ (1.05, 1.00-1.09; per 10 μg/m³), and NO_X (1.01, 1.01-1.02 per 10 μg/m³). Additive effects of PM_2.5 and NO_X exposure and genetic risk were observed. Compared to individuals with a low genetic risk and low air pollution exposure, participants with high air pollution exposure and a high genetic risk had a significantly increased risk of hypertension (PM_2.5: 71% (66%-76%), PM₁₀: 59% (55%-64%), NO_X: 65% (60%-70%)). Our results indicate that long-term exposure to air pollution is associated with an increased risk of hypertension, especially in individuals with a high genetic risk.

Identification of individuals benefiting from the kakaritsuke-yakuzaishi (family pharmacist) system in Japan: a retrospective cohort study using an employment-based health insurance claims database

Background

The kakaritsuke-yakuzaishi system (henceforth, the family pharmacist system) which provides more health services than those by general pharmaceutical practice, was implemented in Japan in April 2016. To distribute medical resources and medical care expenditures appropriately, identifying the possible major beneficiaries of this system is essential. By analyzing administrative claims data through this retrospective cohort study, we identified modifiers of the potential benefits of the system. Further, we integrated the identified modifiers into a scoring system that indicates the possible benefitting subpopulations.

Methods

We obtained data about individuals under 75 years old routinely using community pharmacies in Japan from the JMDC database. We classified the individuals as users or non-users. We used claims related to “choufukutouyaku-sougosayoutou-boushi-kasan (additional therapeutic duplication and drug interaction [TDDI] prevention fees)” filed between April 2018 and March 2020, which indicate that individuals’ prescriptions were modified to adjust leftover drugs or to avoid TDDI as indicators of potential benefit. We estimated adjusted absolute risk differences and 95% confidence intervals for product terms using multiple generalized linear regression models. We included the factors whose 95% confidence interval lower limits did not reach 0 in the multiple logistic regression models for developing a scoring system.

Results

The eligible cohort included 162,340 individuals (1,214 users and 161,126 non-users). The leftover drugs adjustment significantly increased for individuals prescribed antidepressants. However, as only one modifier was identified, we did not develop a scoring system for the leftover drugs adjustment. For TDDI prevention, the following factors were included in the scoring system: being female, being prescribed ≥ 6 drug types, using ≥ 2 medical institutions, and being prescribed proton pump inhibitors, antibiotics, probiotics, or traditional Japanese herbal medicines. The developed scoring system for TDDI prevention scored “female” and “traditional Japanese herbal medicines prescription” factors higher than other factors.

Conclusions

Individuals who are female or prescribed traditional Japanese herbal medicines, or antidepressants may benefit significantly from the family pharmacist system.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-08093-0.

Association and interaction between vitamin D level and metabolic syndrome for non-alcoholic fatty liver disease

INTRODUCTION/OBJECTIVES

Previous studies have shown conflicting results regarding the association between hypovitaminosis D and non-alcoholic fatty liver disease (NAFLD). The aim of this study is to explore the individual and combined effect of hypovitaminosis D and metabolic syndrome (MS) on NAFLD.

MATERIALS AND METHODS

In this cross-sectional study, 874 subjects were enrolled. 25(OH)D was assessed by a sequential competitive immuno-fluoro-assay method. The Fatty Liver Index (FLI) was used for NAFLD screening. Binary logistic regression and additive interaction were performed to investigate the association between vitamin D status, MS and NAFLD.

RESULTS

Severe vitamin D deficiency was found to be positively related to NAFLD, with a higher risk in women than in men (OR = 6.4, 95% CI [2.8-15], p < 0.0001 vs. OR = 5.8, 95% CI [1.9-17.7], p = 0.002). In men, this association was partially masked by obesity. The additive interaction with MS was significant in women but not in men, the relative excess risk due to interaction was of 7.2, 95% CI [1.3-12.9], p = 0.02), the attributable proportion due to the combined effect was of 0.6, 95% CI [0.4-0.8], p < 0.0001. The interaction mechanism is synergistic; the synergy index: was of 2.9, 95% CI [1.6-5.3], p = 0.0006.

CONCLUSION

A positive association has been found between severe vitamin D deficiency and NAFLD. Moreover, an excess risk in women combining both MS and severe vitamin D deficiency was quantified.

Interactive effects of serum ferritin and high sensitivity C-reactive protein on diabetes in hypertensive patients

BACKGROUND

Hypertensive patients, often characterized by chronic inflammation, are susceptible to diabetes. Evidence suggests that the positive association between serum ferritin (SF) and diabetes was affected by high-sensitivity C-reactive protein (hs-CRP), an inflammation marker. We investigate whether there was an interaction between SF and hs-CRP on diabetes in hypertensive patients.

METHODS

We analysed data of 1,735 hypertensive people in this cross-sectional study. Diabetes was diagnosed when fasting blood glucose ≥ 7.0 mmol/L and/or a previous clinical diagnosis of diabetes. Logistic regression models were used to estimate the association of the SF and hs-CRP with diabetes. Multiplicative interaction was evaluated by incorporating a cross-product term for SF and hs-CRP to the logistic regression model. Additive interaction was assessed by calculating the relative excess risk of interaction (RERI) and attributed proportion due to interaction (AP).

RESULTS

In the adjusted analysis, SF (highest vs lowest tertile: odds ratio [OR], 1.61; 95 % confidence interval [CI], 1.20-2.16) was positively associated with diabetes. There was no multiplicative interaction between SF and hs-CRP, but evidence of additive interaction in regard to diabetes (RERI: 0.86; 95 % CI: 0.06-1.67). Compared to the patients with low SF (lower two thirds) and low hs-CRP (≤ 2 mg/L), those with high SF (upper one third) and high hs-CRP (> 2 mg/L) had increased OR for diabetes (adjusted OR: 2.33 [1.65-3.30]), with 37.0 % of the effects attributed to the additive interaction (AP: 0.37; 95 % CI: 0.09-0.65).

CONCLUSIONS

Within a cross-sectional study consisting of hypertensive patients, co-exposure to high SF and high hs-CRP was synergistically associated with diabetes. Dietary intervention or pharmacological treatment to lowering SF concentration may help to reduce diabetes morbidity in hypertensive patient with chronic inflammation.

The risk of preterm birth in combinations of socioeconomic position and mental health conditions in different age groups: a Danish nationwide register-based cohort study

Background

Inequality in preterm birth is a world-wide challenge that has proved difficult for maternity care services to meet. Reducing the inequality requires identification of pregnant women at particularly high risk of preterm birth in order to target interventions. Therefore, the aim was to estimate the risk of preterm birth in women with different combinations of socioeconomic position, mental health conditions, and age.

Methods

In this nationwide register-based cohort study, we included all first-time mothers that gave birth to a singleton liveborn infant in Denmark between 2000 and 2016. The absolute and relative risk of preterm birth (< 37 weeks of gestation) was examined in different combinations of educational level (high, intermediate, and low) and mental health conditions (no, minor, and moderate/severe) in three age strata (≤23, 24–30, and ≥ 31 years). We estimated the relative risk using Poisson regression with a robust error variance. As additive interaction can help identify subgroups where limited resources can be of best use, we measured the attributable proportion to assess the risk that is due to interaction of the different exposures.

Results

Of the 415,523 included first-time mothers, 6.3% gave birth prematurely. The risk of preterm birth increased with decreasing educational level and increasing severity of mental health conditions in all age strata, but most in women aged ≥31 years. The highest absolute risk was 12.9% [95% CI: 11.2;14.8%] in women aged ≥31 years with low education and moderate/severe mental health conditions resulting in a relative risk of 2.23 [95% CI: 1.93–2.58] compared to the unexposed reference group in that age strata. We found positive additive interaction between low education and mental health conditions in women aged 24–30 and ≥ 31 years and between age ≥ 31 years and combinations of mental health conditions and educational levels.

Conclusion

The inequality in preterm birth increased with increasing age. To reduce inequality in preterm birth focused attention on women with higher age further combined with lower educational levels and mental health conditions is essential.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04138-0.

Oral combination of eugenol oleate and miltefosine induce immune response during experimental visceral leishmaniasis through nitric oxide generation with advanced cytokine demand

Conventional therapy of visceral leishmaniasis (VL) remains challenging with the pitfall of toxicity, drug resistance, and expensive. Hence, urgent need for an alternative approach is essential. In this study, we evaluated the potential of combination therapy with eugenol oleate and miltefosine in Leishmania donovani infected macrophages and in the BALB/c mouse model. The interactions between eugenol oleate and miltefosine were found to be additive against promastigotes and amastigotes with xΣFIC 1.13 and 0.68, respectively. Significantly (p < 0.001) decreased arginase activity, increased nitrite generation, improved pro-inflammatory cytokines, and phosphorylated p38MAPK were observed after combination therapy with eugenol oleate and miltefosine. >80% parasite clearance in splenic and hepatic tissue with concomitant nitrite generation, and anti-VL cytokines productions were observed after orally administered miltefosine (5 mg/kg body weight) and eugenol oleate (15 mg/kg body weight) in L. donovani-infected BALB/c mice. Altogether, this study suggested the possibility of an oral combination of miltefosine with eugenol oleate against visceral leishmaniasis.

Joint perceptions of the risk and availability of Cannabis in the United States, 2002-2018

BACKGROUND

Prior work suggests that perceived risk and perceived availability of cannabis independently affect cannabis use. However, perceived risk likely modifies the effect of perceived availability, and vice versa. This study explored trends in joint perceived risk and availability of cannabis from 2002 to 2018 and the relationship between combined perceptions and cannabis use, frequent use, and cannabis use disorder (CUD).

METHODS

National Surveys on Drug Use and Health data (n = 949,285, ages 12+) were used to create combined categories of perceived risk of weekly cannabis use and perceived cannabis availability. Descriptive analyses compared joint perceived risk/availability trends (pre/post-2015 due to survey redesign) overall and stratified by age, gender, past-year cannabis use, frequent use, and CUD. Regression analysis estimated associations between perceived risk/availability and cannabis outcomes.

RESULTS

From 2002 to 2018, the prevalence of perceiving cannabis as low-risk doubled while perceiving cannabis as available remained unchanged. The proportion of individuals perceiving cannabis as Low-risk/Available increased by 86% from 2002 to 2014 (16.8%-31.2%) and 19% from 2015 to 2018 (30.1%-35.8%) while High-risk/Available and High-risk/Unavailable proportions declined. Differing patterns were observed by age and gender. Compared with individuals perceiving cannabis as High-risk/Unavailable, people in all other perception categories had greater risk of all cannabis outcomes. Results were consistent with additive interaction between perceived risk and availability in their effects on cannabis use.

CONCLUSIONS

Trends and associations with cannabis outcomes differ when considering perceived risk and availability independently versus jointly. Longitudinal studies and cannabis policy evaluations would advance understanding of links between cannabis perceptions and use.

The Mediterranean diet and physical activity: better together than apart for the prevention of premature mortality

Diet and physical activity (PA) have been studied extensively in epidemiology as single or combined lifestyle factors; however, their interaction has not been studied thoroughly. Studying potential synergisms between lifestyle components with a comprehensive interaction analysis, including additive measures of interaction, provides key insights into the nature of their joint effect and helps target interventions more effectively. First, a comprehensive review was conducted to assess the potential research gap regarding reported interaction analyses conducted in studies assessing the Mediterranean diet (MedDiet) in combination with PA on all-cause mortality. Thereafter, we prospectively assessed the joint association of the MedDiet with PA on all-cause mortality in the Seguimiento Universidad de Navarra (SUN) cohort, followed by both multiplicative and additive interaction analyses. The conjoint effect of low adherence to the MedDiet and low PA observed an increased risk greater than the individual risk factors, suggesting a potential additive interaction or synergism between both exposures, with relative risk due to interaction (RERI) and (95 % confidence interval (95 % CI)) = 0·46 (–0·83 to 1·75) and attributable proportion (95 % CI) due to interaction of 36 % (–0·62, 1·34). No multiplicative interaction was detected. Studying interactions between lifestyle factors, such as the MedDiet and PA, is particularly relevant given the current research gaps in studying the complexities of combined aspects of lifestyle in comparison with isolated behaviours. Our findings underline the important public health message of adhering to both the MedDiet and PA for the prevention of premature mortality.

Metabolically healthy obesity increases the prevalence of stroke in adults aged 40 years or older: Result from the China National Stroke Screening survey

Debate over the cardio-cerebrovascular risk associated with metabolically healthy obesity (MHO) continues. In this study we investigated the association of MHO with the risk of stroke among 221,114 individuals aged 40 years or older based on data from the China National Stroke Screening and Prevention Project (CNSSPP), a nationally representative cross-sectional study, during 2014 to 2015. Different metabolic health and obesity phenotypes were defined according to the Adult Treatment Panel III (ATP III) criteria, where obesity was defined as a body mass index (BMI) ≥28 kg/m². Logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for stroke risk associated with different metabolically healthy phenotypes. BMI was used to estimate the mediation effect for metabolic abnormalities to stroke. Compared with the metabolically healthy non-obesity (MHNO) group, individuals with MHO (adjusted OR: 1.21, 95% CI: 1.10,1.33), metabolically unhealthy non-obesity (MUNO) (adjusted OR:1.41, 95% CI: 1.36,1.46), or metabolically unhealthy obesity (MUO) (adjusted OR: 1.70, 95% CI: 1.61,1.80) were found to have an increased risk of stroke. The findings were confirmed robustly by various sensitivity analyses and subgroup analyses. Furthermore, obesity and metabolic abnormalities had an additive interaction for stroke risk with an attributable proportion (AP) of 14.0% in females. BMI played a partial mediating role with the proportion of the effect (PE) at 11.1% in the relationship between metabolic abnormalities and stroke. This study strengthens the evidence that management and interventions in the MHO population may contribute to the primary prevention of stroke.

The associations among organophosphate pesticide exposure, oxidative stress, and genetic polymorphisms of paraoxonases in children with attention deficit/hyperactivity disorder

This study will help to clarify the relationship between organophosphate pesticides (OPs) and attention deficit/hyperactivity disorder (ADHD) related to oxidative stress and paraoxonases (PON) polymorphisms to further characterize the gene-environment interaction. This case-control study enrolled 85 children with ADHD and 96 control subjects. Urinary OP levels were analyzed by using gas chromatography-mass spectrometry (GC-MS). Oxidative stress biomarkers, such as 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-nitroguanine (8-NO2-Gua), 8-iso-prostaglandin F2α (8-iso-PGF2α), and 4-hydroxy-2-nonenoic acid-mercapturic acid (HNE-MA), were analyzed by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (S) were calculated to evaluate the additive interactions between OP exposure and PON genetic polymorphism on ADHD. A causal mediation analysis was conducted to clarify the mediation effects of oxidative stress due to OP exposure on ADHD. Children with ADHD had significantly higher DMP (238.95 nmol/g cre. vs. 164.83 nmol/g cre., p value = 0.01) and HNE-MA (30.75 μg/g cre. vs. 18.41 μg/g cre., p value<0.01) concentrations than control children. Children who carried the PON1 GG genotype (rs705379) had low urinary DMP levels, and the level increased with increasing numbers of allele variants. The risk for developing ADHD reached 2.06-fold (OR = 2.06, 95% CI:1.23-3.44) and 1.43-fold (OR = 1.45, 95% CI:1.04-2.03) when the DMP and HNE-MA levels increased by 1 natural log of the concentration, respectively. The estimated AP value was 0.66 (95% CI: 0.17-1.15), indicating that 66% of ADHD cases in DMP-exposed children with the PON1 CT/TT (rs705381) genotype were due to gene-environment interactions. No significant mediation of HNE-MA was observed between DMP exposure and the risk of ADHD. The estimated proportion mediated was only 7.0% (95% CI: -0.08-0.46). This research suggests the role of OP exposure in the occurrence of ADHD after adjusting for covariates.

The impact of nocturnal road traffic noise, bedroom window orientation, and work-related stress on subjective sleep quality: results of a cross-sectional study among working women

Objective

To examine the effect of work-related stress and road noise exposure on self-rated sleep and potential additive interaction effects.

Methods

Sleep and predictor variables were surveyed within two subsamples with 2191 and 1764 working women in a cross-sectional study. Sleep was assessed using a single question on general sleep quality and four questions on specific sleep problems and subsequently dichotomized (poor sleep vs. no poor sleep). Work-related stress was operationalized by job strain and effort-reward imbalance. Nocturnal exposure to road traffic noise was assessed as (a) the orientation of the bedroom window to a quiet façade vs. a low-, medium- or high-trafficked street and (b) energy-equivalent sound pressure levels for night-time modelled at the most exposed façade (L_night). We distinguished between low (< 45 dB(A)), medium (45–50 dB(A)) and high exposure (> 50 dB(A)).

Results

Poor sleep was associated with job strain and effort-reward imbalance. The prevalence of poor sleep did not increase with increasing L_night, but bedroom window orientation showed a non-significant trend. A quiet façade had a protective effect on sleep in each L_night category. We found a non-significant trend for an additive interaction between bedroom window orientation and job strain.

Conclusion

Noise levels modelled for the most exposed façade likely overestimate the actual exposure and thus may not be a precise predictor of poor sleep. Bedroom window orientation seems more relevant. Potential additive interaction effects between bedroom window orientation and job strain should be considered when interpreting epidemiological study results on noise-induced sleep disturbances.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00420-021-01696-w.

Familial risk for endometriosis and its interaction with smoking, age at menarche and body mass index: a population-based cohort study among siblings

OBJECTIVE

To quantify familial risk of endometriosis among full siblings and examine interactions between family history and smoking, age at menarche or body mass index (BMI).

DESIGN, SETTING AND POPULATION

Population-based nationwide cohort study.

METHODS

Using data from the Korean National Health Insurance and Screening Programme databases on kinship, healthcare utilisation, lifestyle and anthropometrics, we identified 2 109 288 women with full siblings and their environmental risk factors from 2002 to 2018. Familial risks were estimated using Cox proportional-hazards models, represented as incidence risk ratios (IRR) with 95% CI. Interaction between family history and smoking, age at menarche or BMI were assessed on an additive scale.

MAIN OUTCOME MEASURES

IRR of endometriosis among women with and without affected siblings.

RESULTS

From 19 195 women with affected siblings, 1126 developed endometriosis with an incidence of 35.45/10 000 person-years. Familial risk of endometriosis with versus without affected siblings was increased to IRR 2.75 (95% CI 2.25-3.36), and the highest risk was with affected twins (IRR 6.98; 95% CI 4.19-11.62). Women with both a family history and either smoking, early menarche or low BMI had a significantly higher risk of endometriosis compared with the general population and can be regarded as a high-risk group, the IRRs were 4.28 (95% CI 2.43-7.55), 3.47 (95% CI 2.82-4.26) and 3.09 (95% CI 2.68-3.56), respectively. Substantial effect modification of the associations was noted by smoking and early menarche, as their combined risk with family history exceeded the sum of their individual risks, which was also statistically significant.

CONCLUSION

Genetic factors are the primary contributor to the familial aggregation of endometriosis. Significant gene-environment interaction exists between family history and smoking or early menarche.

Considerations when conducting moderation analysis with a binary outcome: Applications to clinical and social pharmacy research

Clinical and social pharmacy researchers often have questions regarding contingencies of effects (i.e., moderation) that are tested by including interactions in statistical models. Much of the available literature for estimating and testing effects that emanate from moderation models is based on extensions of the linear model with continuous outcomes. Binary (or dichotomous) outcome variables, such as prescription-medication misuse versus no misuse, are commonly encountered by clinical and social pharmacy researchers. In moderation analysis, binary outcomes have led to an increased focus on the fact that measures of interaction are scale-dependent; thus, researchers may need to consider both additive interaction and multiplicative interaction. Further complicating interpretation is that the statistical model chosen for an interaction can provide different answers to questions of moderation. This manuscript will: 1) identify research questions in clinical and social pharmacy that necessitate the use of these statistical methods, 2) review statistical models that can be used to estimate effects when the outcome of interest is binary, 3) review basic concepts of moderation, 4) describe the challenges inherent in conducting moderation analysis when modeling binary outcomes, and 5) demonstrate how to conduct such analyses and interpret relevant statistical output (including interpretations of interactions on additive and multiplicative scales with a focus on identifying which statistical models for binary outcomes lead to which measure of interaction). Although much of the basis for this paper comes from research in epidemiology, recognition of these issues has occurred in other disciplines.

Association of body mass index and waist circumference with high blood pressure in older adults

BACKGROUND

The relationship between obesity and prevalent high blood pressure in older adults has predominantly been estimated using categorical measures of body mass index (BMI) and waist circumference (WC), masking the shape of the dose-response relationship. We aimed to examine the precise relationship of BMI, WC with high blood pressure and to assess the appropriate level of BMI and WC for high blood pressure.

METHODS

We examined data for 126,123 individuals in Xinzheng city aged ≥60 years from a population based study from January to December 2019. Logistic regression and restricted cubic spline models were applied to assess the relationship and the appropriate level of BMI and WC for high blood pressure. An additive interaction analysis was used to test synergistic effects between a higher BMI and WC for high blood pressure.

RESULTS

The full-adjusted odds ratios (ORs) with 95% confidence intervals (CIs) of an increase of 1 kg/m² in BMI and 1 cm in WC for high blood pressure were 1.084 (1.080-1.087) and 1.026(1.024-1.027), respectively. Multivariable adjusted restricted cubic spline analyses showed the nonlinear relationships of BMI and WC with high blood pressure in both men and women (all P < 0.001). The risk of high blood pressure increased steeply with increasing BMI from ≥25 kg/m² and WC ≥ 88 cm or 86 cm for males and females, respectively. And we observed a significant additive interaction between a higher BMI and WC such that the prevalence of high blood pressure was significantly enhanced.

CONCLUSION

These findings suggest increased high blood pressure prevalence in the older adults with increased BMI and WC. BMI ≤ 25 kg/m2 and WC ≤ 88 cm or 86 cm for males and females may be the best suggestion with regard to primary prevention of high blood pressure in older adults.

Household mold exposure interacts with inflammation-related genetic variants on childhood asthma: a case-control study

BACKGROUND

A number of studies have examined the association between mold exposure and childhood asthma. However, the conclusions were inconsistent, which might be partly attributable to the lack of consideration of gene function, especially the key genes affecting the pathogenesis of childhood asthma. Research on the interactions between genes and mold exposure on childhood asthma is still very limited. We therefore examined whether there is an interaction between inflammation-related genes and mold exposure on childhood asthma.

METHODS

A case-control study with 645 asthmatic children and 910 non-asthmatic children aged 3-12 years old was conducted. Eight single nucleotide polymorphisms (SNPs) in inflammation-related genes were genotyped using MassARRAY assay. Mold exposure was defined as self-reported visible mold on the walls. Associations between visible mold exposure, SNPs and childhood asthma were evaluated using logistic regression models. In addition, crossover analyses were used to estimate the gene-environment interactions on childhood asthma on an additive scale.

RESULTS

After excluding children without information on visible mold exposure or SNPs, 608 asthmatic and 839 non-asthmatic children were included in the analyses. Visible mold exposure was reported in 151 asthmatic (24.8%) and 119 non-asthmatic children (14.2%) (aOR 2.19, 95% CI 1.62-2.97). The rs7216389 SNP in gasdermin B gene (GSDMB) increased the risk of childhood asthma with each C to T substitution in a dose-dependent pattern (additive model, aOR 1.32, 95% CI 1.11-1.57). Children carrying the rs7216389 T allele and exposed to visible mold dramatically increased the risk of childhood asthma (aOR 3.21; 95% CI 1.77-5.99). The attributable proportion due to the interaction (AP: 0.47, 95% CI 0.03-0.90) and the relative excess risk due to the interaction (RERI: 1.49, 95% CI 0-2.99) were statistically significant.

CONCLUSIONS

In the present study, there was a significant additive interaction between visible mold exposure and rs7216389 SNP on childhood asthma. Future studies need to consider the gene-environment interactions when exploring the risk factors of childhood asthma.

Additive interaction of mid- to late-life depression and cerebrovascular disease on the risk of dementia: a nationwide population-based cohort study

Background

Dementia is a progressive neurocognitive disease with a substantial social burden. No apparent breakthroughs in treatment options have emerged so far; thus, disease prevention is essential for at-risk populations. Depression and cerebrovascular disease (CVD) are independent risk factors for dementia, but no studies have examined their interaction effect on dementia risk. This study aimed to identify the association of depression and CVD with the risk of dementia and evaluate whether dementia risk among patients with comorbid depression and CVD is higher than the sum of the individual risk due to each condition.

Methods

A population-based cohort study was conducted to analyze the Korean National Health Insurance Service-National Sample Cohort data of all individuals over 50 years of age. Individuals who had not been diagnosed with dementia at baseline were included and followed up from January 1, 2005, to December 31, 2013. A time-varying Cox proportional hazard regression model adjusted for potential confounding factors was used for the analysis. The interaction between depression and CVD was estimated based on the attributable proportion (AP), relative excess risk due to interaction (RERI), synergy index (SI), and multiplicative-scale interaction.

Results

A total of 242,237 participants were included in the analytical sample, of which 12,735 (5.3%) developed dementia. Compared to that for participants without depression or CVD, the adjusted hazard ratio for the incidence of dementia for those with depression alone was 2.35 (95% confidence interval [CI] 2.21–2.49), CVD alone was 3.25 (95% CI 3.11–3.39), and comorbid depression and CVD was 5.02 (95% CI 4.66–5.42). The additive interaction between depression and CVD was statistically significant (AP—0.08, 95% CI 0.01–0.16; RERI—0.42, 95% CI 0.03–0.82; SI—1.12, 95% CI 1.01–1.24). The multiplicative interaction was significant too, but the effect was negative (0.66, 95% CI 0.60–0.73).

Conclusions

In this population-based nationwide cohort with long-term follow-up, depression and CVD were associated with an increased risk of dementia, and their coexistence additively increased dementia risk more than the sum of the individual risks.

Synergic effect between high temperature and air pollution on mortality in Northeast Asia

High temperature and air pollutants have been reported as potential risk factors of mortality. Previous studies investigated interaction between the two variables; however, the excess death risk due to the synergic effect (i.e. interaction on the additive scale) between the two variables has not been investigated adequately on a multi-country scale. This study aimed to assess the excess death risk due to the synergism between high temperature and air pollution on mortality using a multicity time-series analysis. We collected time-series data on mortality, weather variables, and four air pollutants (PM₁₀, O₃, NO₂, and CO) for 16 metropolitan cities of three countries (Japan, Korea, and Taiwan) in Northeast Asia (1979-2015). Quasi-Poisson time-series regression and meta-analysis were used to estimate the additive interaction between high temperature and air pollution. The additive interaction was measured by relative excess risk due to interaction (RERI) index. We calculated RERI with relative risks (RR) of the 99th/10th, 90th/90th, and 99th/90th percentiles of temperature/air pollution metrics, where risk at the 90th/10th percentiles of temperature/air pollution metrics was the reference category. This study showed that there may exist positive and significant excess death risks due to the synergism between high temperature and air pollution in the total population for all pollutants (95% lower confidence intervals of all RERIs>0 or near 0). In final, we measured quantitatively the excess death risks due to synergic effect between high temperature and air pollution, and the synergism should be considered in public health interventions and a composite warning system.

Estimating Additive Interaction Effect in Stratified Two-Phase Case-Control Design

BACKGROUND AND AIMS

There is considerable interest in epidemiology to estimate an additive interaction effect between two risk factors in case-control studies. An additive interaction is defined as the differential reduction in absolute risk associated with one factor between different levels of the other factor. A stratified two-phase case-control design is commonly used in epidemiology to reduce the cost of assembling covariates. It is crucial to obtain valid estimates of the model parameters by accounting for the underlying stratification scheme to obtain accurate and precise estimates of additive interaction effects. The aim of this paper is to examine the properties of different methods for estimating model parameters and additive interaction effects under a stratified two-phase case-control design.

METHODS

Using simulations, we investigate the properties of three existing methods, namely stratum-specific offset, inverse-probability weighting, and multiple imputation for estimating model parameters and additive interaction effects. We also illustrate these properties using data from two published epidemiology studies.

RESULTS

Simulation studies show that the multiple imputation method performs well when both the true and analysis models are additive (i.e., does not include multiplicative interaction terms) but does not provide a discernible advantage over the offset method when the analysis models are non-additive (i.e., includes multiplicative interaction terms). The offset method exhibits the best overall properties when the analysis model contains multiplicative interaction effects.

CONCLUSION

When estimating additive interaction between risk factors in stratified two-phase case-control studies, we recommend estimating model parameters using multiple imputation when the analysis model is additive, and we recommend the offset method when the analysis model is non-additive.

Interaction between diet- and exercise-lifestyle and phthalates exposure on sex hormone levels

Phthalate can affect sex hormones secretion. Exercise and diet habits affect sex hormones levels. However, interaction of phthalates exposure and diet or exercise habits with sex hormones is unclear. We enrolled 106 residents aged 11-88 years (48 males and 58 females) from two communities, Wuhan city, China during the winter of 2014 and summer of 2015. Data were collected on socio-demographic characteristics and lifestyle by a questionnaire in two seasons. Participants provided the blood and urine samples over 3 consecutive days for measuring sex hormones and urinary phthalate metabolites. We assessed the associations of urinary phthalate metabolites levels, lifestyle with hormones levels, the interaction of phthalate exposure and lifestyle with hormones levels using multivariate binary logistic regression models. High urinary mono-(2-ethyl-5-oxyhexyl) phthalate (MEOHP) levels and no exercise had an additive interaction on abnormal serum progesterone (PROG) levels in winter as well as on abnormal serum follicle-stimulating hormone (FSH) or luteinizing hormone (LH) levels in summer. High urinary MEOHP levels and red meat intake (>1 time/day) had an additive interaction with abnormal levels of serum FSH only in the winter. Phthalates exposure may confer differential susceptibility to abnormal hormones levels in individuals with no exercise or eating meat >1 time/day.

Additive interaction of snoring and body mass index on the prevalence of metabolic syndrome among Chinese coal mine employees: a cross-sectional study

BACKGROUND

Although snoring has been previously reported to be associated with metabolic syndrome (MetS), its interaction with body mass index(BMI) on MetS remains unclear. We aimed to examine the individual effects and possible interaction between snoring and BMI on MetS.

METHODS

From July 2013 to December 2013, 3794 employees of coal mining enterprises aged 18 to 65 were recruited from Shanxi province of China. The individual effects were assessed by multivariable logistic regression model. Additive interaction was evaluated by calculating the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index(S).

RESULTS

We found that, after adjusting for potential confounders, odds ratio (OR) and 95% CI for MetS was 1.30 (1.09, 1.56) in occasional snorers and 1.50 (1.24, 1.82) in habitual snorers compared with non-snorers. BMI ≥ 24 was related to high risk of MetS (OR, 3.27; 95% CI, 2.93-3.63). Significant additive interaction between snoring and BMI on MetS was detected. The estimates and 95% CI of the RERI, AP and S were 1.89 (0.67, 3.24), 0.23 (0.08, 0.38), and 1.37 (1.11, 1.75), respectively. However, stratified by workplace, the additive interaction was only significant among underground front-line and ground workers.

CONCLUSIONS

Both Snoring and BMI were related to high risk of Mets. Moreover, there are additive interaction between snoring and BMI. Snorers who worked underground front-line and ground are more susceptible to the negative impact of being overweight on MetS.

Individual and combined effects of multiple global change drivers on terrestrial phosphorus pools: A meta-analysis

Human activity-induced global change drivers have dramatically changed terrestrial phosphorus (P) dynamics. However, our understanding of the interactive effects of multiple global change drivers on terrestrial P pools remains elusive, limiting their incorporation into ecological and biogeochemical models. We conducted a meta-analysis using 1751 observations extracted from 283 published articles to evaluate the individual, combined, and interactive effects of elevated CO₂, warming, N addition, P addition, increased rainfall, and drought on P pools of plant (at both single-plant and plant-community levels), soil and microbial biomass. Our results suggested that (1) terrestrial P pools showed the most sensitive responses to the individual effects of warming and P addition; (2) P pools were consistently stimulated by P addition alone or in combination with simultaneous N addition; (3) environmental and experimental setting factors such as ecosystem type, climate, and latitude could significantly influence both the individual and combined effects; and (4) the interactive effects of two-driver pairs across multiple global change drivers are more likely to be additive rather than synergistic or antagonistic. Our findings highlighting the importance of additive interactive effects among multiple global change drivers on terrestrial P pools would be useful for incorporating P as controls on ecological processes such as photosynthesis and plant growth into ecosystem models used to analyze effects of multiple drivers under future global change.

LncRNA LCPAT1 Mediates Smoking/ Particulate Matter 2.5-Induced Cell Autophagy and Epithelial-Mesenchymal Transition in Lung Cancer Cells via RCC2

BACKGROUND/AIMS

Ecological studies have shown that air pollution and prevalence of cigarette smoking are positively correlated. Evidence also suggests a synergistic effect of cigarette smoking and PM2.5 exposure (Environmental Particulate Matter ≤ 2.5 µm in diameter) on lung cancer risk. We aimed to evaluate the interaction between smoking prevalence and PM2.5 pollution in relation to lung cancer mortality and determine its underlying mechanisms in vitro.

METHODS

"MOVER" method was used to analyze the interaction between smoking prevalence and PM2.5 pollution in relation to lung cancer mortality. Cell autophagy and malignant behaviors induced by cigarette smoke extract (CSE) and PM2.5 exposure were examined in vitro. Gene expression was examined by qRT-PCR and western blot. RNA and protein interaction was determined using a RNA binding protein immunoprecipitation assay.

RESULTS

An increased risk for lung cancer death (RERI (the relative excess risk) =0.28) was observed with a synergistic interaction between cigarette smoking and PM2.5 pollution. Cell migration, invasion, EMT (epithelial-mesenchymal transition) and autophagy were elevated when lung cancer cells were treated with CSE and PM2.5 in combination. A lncRNA, named lung cancer progression-association transcript 1 (LCPAT1), was up-regulated after the treatment of CSE and PM2.5, and knocking down the lncRNA impaired the effect of CSE and PM2.5 on lung cancer cells. In addition, LCPAT1 was shown to bind to RCC2, and RCC2 mediated the effect of LCPAT1 on cell autophagy, migration, invasion and EMT in lung cancer.

CONCLUSIONS

Our results suggest that combined exposure to CSE and PM2.5 induces LCPAT1 expression, which up-regulates autophagy, and promotes lung cancer progression via RCC2.

Relative importance of competition and plant-soil feedback, their synergy, context dependency and implications for coexistence

Plants interact simultaneously with each other and with soil biota, yet the relative importance of competition vs. plant-soil feedback (PSF) on plant performance is poorly understood. Using a meta-analysis of 38 published studies and 150 plant species, we show that effects of interspecific competition (either growing plants with a competitor or singly, or comparing inter- vs. intraspecific competition) and PSF (comparing home vs. away soil, live vs. sterile soil, or control vs. fungicide-treated soil) depended on treatments but were predominantly negative, broadly comparable in magnitude, and additive or synergistic. Stronger competitors experienced more negative PSF than weaker competitors when controlling for density (inter- to intraspecific competition), suggesting that PSF could prevent competitive dominance and promote coexistence. When competition was measured against plants growing singly, the strength of competition overwhelmed PSF, indicating that the relative importance of PSF may depend not only on neighbour identity but also density. We evaluate how competition and PSFs might interact across resource gradients; PSF will likely strengthen competitive interactions in high resource environments and enhance facilitative interactions in low-resource environments. Finally, we provide a framework for filling key knowledge gaps and advancing our understanding of how these biotic interactions influence community structure.

The interactions among organophosphate pesticide exposure, oxidative stress, and genetic polymorphisms of dopamine receptor D4 increase the risk of attention deficit/hyperactivity disorder in children

OBJECTIVE

The aim of this study was to clarify the association between organophosphate pesticides (OPs) and attention-deficit/hyperactivity disorder (ADHD) related to oxidative stress and genetic polymorphisms.

METHODS

This case-control study enrolled 93 children with ADHD and 112 control children in north Taiwan. Six dialkyl phosphate (DAP) metabolites of OPs and oxidative stress biomarkers were analyzed. Polymorphisms of the dopamine receptor D4 gene (DRD4) were identified.

RESULTS

Children with ADHD had significantly higher dimethylphosphate (DMP, 236.69nmol/g cre. vs. 186.84nmol/g cre., p value = 0.01) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA, 28.95µg/g cre. vs. 16.55µg/g cre., p value<0.01) concentrations than control children. Children who carried DRD4 GA/AA genotypes (rs752306) were less likely than those who carried the DRD4 GG genotype to have ADHD (odds ratio [OR]: 0.45, 95% CI: 0.24-0.84). The estimated value of the AP (attributable proportion due to interaction) was 0.59 (95% CI: 0.13-1.05), indicating that 59% of ADHD cases in DMP-exposed children with the DRD4 GG genotype were due to the gene-environment interaction. After adjustment for other covariates, children who carried the DRD4 GG genotype, had been exposed to high DMP levels (more than the median), and had high HNE-MA levels had a significantly increased risk for developing ADHD (OR = 11.74, 95% CI: 2.12-65.04).

CONCLUSION

This study indicated a gene-environment interaction in the risk of ADHD in children. The association between DMP and ADHD in children might relate to the mechanism of lipid peroxidation. Dose-response relationships and the combined effects of OPs, oxidative stress, and genetic polymorphism on ADHD should not be neglected.

Interactions between cigarette smoking and ambient PM2.5 for cardiovascular mortality

Associations between long-term exposure to ambient fine particulate matter (PM_2.5) and all-cause and cardiovascular mortality are well documented however less is known regarding possible interactions with cigarette smoking. We previously reported a supra-additive synergistic relationship between PM_2.5 and cigarette smoking for lung cancer mortality. Here we examine interactions for all-cause and cardiovascular mortality among 429,406 current or never smoking participants in the prospective American Cancer Society Cancer Prevention Study-II with modeled PM_2.5 concentrations. Cox proportional and additive hazards models were used to estimate mortality associations and interactions on the multiplicative and additive scales. A total of 146,495 all-cause and 64,339 cardiovascular (plus diabetes) deaths were observed. The hazard ratio (HR) (95% confidence interval (CI)) for cardiovascular mortality for high vs. low PM_2.5 exposure (>14.44µg/m³ vs ≤10.59µg/m³, 75th vs 25th percentile) was 1.09 (95% CI 1.05, 1.12) in never smokers. The HR for cigarette smoking was 1.89 (95% CI 1.82, 1.96) in those with low PM_2.5. The HR for both high PM_2.5 and cigarette smoking was 2.08 (95% CI 2.00, 2.17). A small significant excess relative risk due to interaction (0.10; 95% CI 0.02, 0.19) was observed. Quantification of the public health burden attributed to the interaction between PM_2.5 and cigarette smoking indicated a total of 32 (95% CI -6, 71) additional cardiovascular deaths per 100,000 person-years due to this interaction. In conclusion, PM_2.5 was associated with all-cause and cardiovascular mortality in both smokers and never smokers, with some evidence for a small additive interaction with cigarette smoking. Reductions in cigarette smoking will result in the greatest impact on reducing all-cause and cardiovascular death at the levels of PM_2.5 observed in this study. However, reductions in PM_2.5 will also contribute to preventing a proportion of mortality attributed to cigarette smoking.

The effect of low parental warmth and low monitoring on disordered eating in mid-adolescence: Findings from the Australian Temperament Project

OBJECTIVE

To investigate the interactions between low parental warmth and monitoring at age 13-14 years and disordered eating attitudes and behaviours at age 15-16 years.

METHOD

Data on 1300 (667 females) adolescents and their parents were drawn from The Australian Temperament Project (ATP), a 30 year (15 wave) population based longitudinal study of social-emotional development. Parent participants completed surveys on parenting practices in late childhood, and adolescent participants reported disordered eating using the drive for thinness and bulimia subscales of the Eating Disorder Inventory (EDI) and an additional body dissatisfaction scale. Interaction was examined on the additive scale by estimating super-additive risk; i.e., risk in excess of the sum of individual risks.

RESULTS

For boys, neither parental warmth or monitoring, nor their interaction, was related to disordered eating. For girls, low parental warmth (alone) was associated with bulimic behaviours. In contrast, exposure to both low monitoring and warmth was associated with ∼3½-fold, ∼4-fold and ∼5-fold increases in the odds of reporting body dissatisfaction, drive for thinness and bulimia, respectively. For body dissatisfaction and drive for thinness, risk associated with joint exposure exceeded the sum of individual risks, suggesting an additive interaction between parenting styles.

CONCLUSION

Further investment in family-level interventions that focus on promoting parental monitoring behaviour and a warm parent-child relationship remain important strategies for preventing a range of disordered eating behaviours in adolescents.

Rapid Repeat Pregnancy in Brazilian Adolescents: Interaction between Maternal Schooling and Age

STUDY OBJECTIVE

An association between rapid repeat pregnancy (RRP; occurring within a birth interval of up to 24 months) and undesirable obstetric and perinatal outcomes has been shown, especially among adolescents and women without adequate schooling. The objective of this study was to evaluate the effect of the interaction between maternal schooling and age on the incidence of RRP. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: A nonconcurrent cohort study was carried out using probabilistic record linkage techniques. The 59,400 linked records of singleton live-born infants delivered in 2002 whose mothers were up to 29 years old and lived in Rio de Janeiro City were evaluated.

RESULTS

Compared with young adults with adequate schooling, the adjusted risk ratio for RRP for adolescents with inadequate schooling was 2.1 (95% confidence interval, 1.8-2.4). The attributable proportion was 0.16 (95% confidence interval, 0.02-0.29).

CONCLUSION

Young maternal age and inadequate schooling interact, increasing RRP.

The genetic interacting landscape of 63 candidate genes in Major Depressive Disorder: an explorative study

Background

Genetic contributions to major depressive disorder (MDD) are thought to result from multiple genes interacting with each other. Different procedures have been proposed to detect such interactions. Which approach is best for explaining the risk of developing disease is unclear.

This study sought to elucidate the genetic interaction landscape in candidate genes for MDD by conducting a SNP-SNP interaction analysis using an exhaustive search through 3,704 SNP-markers in 1,732 cases and 1,783 controls provided from the GAIN MDD study. We used three different methods to detect interactions, two logistic regressions models (multiplicative and additive) and one data mining and machine learning (MDR) approach.

Results

Although none of the interaction survived correction for multiple comparisons, the results provide important information for future genetic interaction studies in complex disorders. Among the 0.5% most significant observations, none had been reported previously for risk to MDD. Within this group of interactions, less than 0.03% would have been detectable based on main effect approach or an a priori algorithm. We evaluated correlations among the three different models and conclude that all three algorithms detected the same interactions to a low degree. Although the top interactions had a surprisingly large effect size for MDD (e.g. additive dominant model P_uncorrected = 9.10E-9 with attributable proportion (AP) value = 0.58 and multiplicative recessive model with P_uncorrected = 6.95E-5 with odds ratio (OR estimated from β3) value = 4.99) the area under the curve (AUC) estimates were low (< 0.54). Moreover, the population attributable fraction (PAF) estimates were also low (< 0.15).

Conclusions

We conclude that the top interactions on their own did not explain much of the genetic variance of MDD. The different statistical interaction methods we used in the present study did not identify the same pairs of interacting markers. Genetic interaction studies may uncover previously unsuspected effects that could provide novel insights into MDD risk, but much larger sample sizes are needed before this strategy can be powerfully applied.