Cigarette smoking and cerebral blood flow in a cohort of middle-aged adults

Investigating Modifiable Risk Factors Across Dementia Subtypes: Insights from the UK Biobank

This study investigates the relationship between modifiable risk factors and dementia subtypes using data from 460,799 participants in the UK Biobank. Utilizing univariate Cox proportional hazards regression models, we examined the associations between 83 modifiable risk factors and the risks of all-cause dementia (ACD), Alzheimer's disease (AD), and vascular dementia (VD). Composite scores for different domains were generated by aggregating risk factors associated with ACD, AD, and VD, respectively, and their joint associations were assessed in multivariable Cox models. Additionally, population attributable fractions (PAF) were utilized to estimate the potential impact of eliminating adverse characteristics of the risk domains. Our findings revealed that an unfavorable medical history significantly increased the risk of ACD, AD, and VD (hazard ratios (HR) = 1.88, 95% confidence interval (95% CI): 1.74-2.03, p < 0.001; HR = 1.80, 95% CI: 1.54-2.10, p < 0.001; HR = 2.39, 95% CI: 2.10-2.71, p < 0.001, respectively). Blood markers (PAF = 12.1%; 17.4%) emerged as the most important risk domain for preventing ACD and VD, while psychiatric factors (PAF = 18.3%) were the most important for preventing AD. This study underscores the potential for preventing dementia and its subtypes through targeted interventions for modifiable risk factors. The distinct insights provided by HR and PAF emphasize the importance of considering both the strength of the associations and the population-level impact of dementia prevention strategies. Our research provides valuable guidance for developing effective public health interventions aimed at reducing the burden of dementia, representing a significant advancement in the field.

Risk factors for smoking in adolescence: evidence from a cross-sectional survey in Switzerland

BACKGROUND

Cigarette smoking during adolescence is a major public health concern with far-reaching health implications. Adolescents who smoke are at an increased risk of developing long-term health problems and are more likely to continue smoking into adulthood. Therefore, it is vital to identify and understand the risk factors that contribute to adolescent smoking - which in turn facilitate the development of targeted prevention and intervention programs.

METHODS

Data was drawn from a cross-sectional survey conducted between October and December 2021, encompassing adolescents of adolescents aged 14 to 19 residing in Switzerland (n = 2,683). Multiple logistic regression analysis was employed to explore which demographic, household, behavioural and psychographic factors are associated with current smoking status.

RESULTS

The regression results showed higher odds of smoking for female respondents (OR 1.39; p-value 0.007); older adolescents (OR 1.30; p-value < 0.001); those living in the French-speaking part of Switzerland (OR 1.39; p-value 0.021), in suburban areas (OR 1.35; p-value 0.023) and with a smoker in the same household (OR 2.41; p-value < 0.001); adolescents consuming alcohol (OR 4.10; p-value < 0.001), cannabis products (OR 6.72; p-value < 0.001) and hookah (OR 5.07; p-value < 0.001) at least once a month; respondents not engaging in sports (OR 1.90; p-value < 0.001) or music (OR 1.42; p-value 0.031) as top five leisure activities and those experiencing high stress levels at home (OR 1.74; p-value < 0.001). Adolescents with high scores in health awareness (OR 0.33; p-value < 0.001), on the relational self-esteem scale (OR 0.78; p-value 0.054) and on the general well-being scale (OR 0.52; p-value 0.022) were less likely to smoke than their counterparts with lower scores. High risk-seeking was associated with higher odds of smoking (OR 2.15; p-value < 0.001).

CONCLUSIONS

Our results suggest the importance of a comprehensive approach at both individual and institutional levels to reduce smoking rates in adolescents. More specifically, a holistic strategy that encompasses adolescents, families, schools and policymakers ranging from strengthening adolescents' self-esteem, smoking cessation support for parents, to increasing engagement in musical and physical activities, and enhancing health awareness in the school curriculum.

The Role of Microglia in Sex- and Region-Specific Blood-Brain Barrier Integrity During Nicotine Withdrawal

Background

Smoking is the largest preventable cause of death and disease in the United States, with <5% of quit attempts being successful. Microglia activation and proinflammatory neuroimmune signaling in reward neurocircuitry are implicated in nicotine withdrawal symptomology. Microglia are integral regulators of blood-brain barrier (BBB) functionality as well; however, whether the effects of nicotine withdrawal on microglia function impact BBB integrity is unknown.

Methods

Mice were treated with chronic nicotine (12 mg/kg/day) and subjected to 48 hours nicotine withdrawal. Regional BBB permeability, together with messenger RNA and protein expression of tight junction proteins, were assessed. PLX5622 chow was used to deplete microglia to evaluate the role of microglia in regulating BBB integrity and nicotine withdrawal symptomology.

Results

Female mice had higher baseline BBB permeability in the prefrontal cortex and hippocampus than males. Nicotine withdrawal further exacerbated the BBB permeability selectively in the prefrontal cortex of females. These effects were concurrent with prefrontal cortex alterations in a subset of tight junction proteins with increased proinflammatory responses following nicotine withdrawal in females. Depletion of microglia via PLX5622 treatment prevented all these molecular effects and attenuated withdrawal-induced anxiety-like behavior in female mice.

Conclusions

These results are the first to show sex differences in regional BBB permeability during nicotine withdrawal. This represents a possible link to both the reduced smoking cessation success seen in women and women's increased risk for smoking-related neurovascular disorders. Furthermore, these findings open an avenue for sex-specific therapeutics that target microglia and BBB dysfunction during nicotine withdrawal in women.

Longstanding smoking associated with frontal brain lobe atrophy: a 32-year follow-up study in women

OBJECTIVE

To examine the association between midlife tobacco smoking and late-life brain atrophy and white matter lesions.

METHODS

The study includes 369 women from the Prospective Population Study of Women in Gothenburg, Sweden. Cigarette smoking was reported at baseline 1968 (mean age=44 years) and at follow-up in 1974-1975 and 1980-1981. CT of the brain was conducted 32 years after baseline examination (mean age=76 years) to evaluate cortical atrophy and white matter lesions. Multiple logistic regressions estimated associations between midlife smoking and late-life brain lesions. The final analyses were adjusted for alcohol consumption and several other covariates.

RESULTS

Smoking in 1968-1969 (adjusted OR 1.85; 95% CI 1.12 to 3.04), in 1974-1975 (OR 2.37; 95% CI 1.39 to 4.04) and in 1980-1981 (OR 2.47; 95% CI 1.41 to 4.33) were associated with late-life frontal lobe atrophy (2000-2001). The strongest association was observed in women who reported smoking at all three midlife examinations (OR 2.63; 95% CI 1.44 to 4.78) and in those with more frequent alcohol consumption (OR 6.02; 95% CI 1.74 to 20.84). Smoking in 1980-1981 was also associated with late-life parietal lobe atrophy (OR 1.99; 95% CI 1.10 to 3.58). There were no associations between smoking and atrophy in the temporal or occipital lobe, or with white matter lesions.

CONCLUSION

Longstanding tobacco smoking was mainly associated with atrophy in the frontal lobe cortex. A long-term stimulation of nicotine receptors in the frontal neural pathway might be harmful for targeted brain cell.

Association of Electrical Cardioversion with Brain Perfusion and Cognitive Function in Patients with Atrial Fibrillation

BACKGROUND

The association of atrial fibrillation (AF) and brain perfusion (BP) has not been well-defined. This study aimed to determine the association of persistent AF with BP and cognition, in comparison to control subjects and with regards to electrical cardioversion (ECV).

METHODS

This study compared 25 patients with persistent AF undergoing elective ECV with 16 age/sex-matched controls. We measured regional BP by using the magnetic resonance (MRI) arterial spin labelling technique. Cognitive function was assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) cognitive function index. Measurements were performed at baseline and 6 weeks after ECV.

RESULTS

There was no significant difference in BP between AF patients and control subjects (p > 0.05). Following the ECV, there was a significant improvement in BP in 15 patients who maintained sinus rhythm, while there was no significant change in the recurrence group (297 ± 24 before vs. 328 ± 37 after ECV, p = 0.008, and 297 ± 22 before vs. 307 ± 24 after ECV, p = 0.45, respectively). There was no difference in the cognitive assessment between AF patients and control subjects, as well as before and after ECV within the AF group (52.2 ± 9.6 vs. 51.2 ± 6.2, p = 0.71 and 53 ± 10 vs. 54 ± 9, p = 0.46, respectively).

CONCLUSIONS

This study did not show difference in BP between persistent AF patients and matched control subjects. Restoration of sinus rhythm was associated with significantly improved BP. There was no association of ECV and changes in cognitive function.

Cerebral blood flow in striatum is increased by partial dopamine agonism in initially antipsychotic-naïve patients with psychosis

BACKGROUND

Resting cerebral blood flow (rCBF) in striatum and thalamus is increased in medicated patients with psychosis, but whether this is caused by treatment or illness pathology is unclear. Specifically, effects of partial dopamine agonism, sex, and clinical correlates on rCBF are sparsely investigated. We therefore assessed rCBF in antipsychotic-naïve psychosis patients before and after aripiprazole monotherapy and related findings to sex and symptom improvement.

METHODS

We assessed rCBF with the pseudo-Continuous Arterial Spin Labeling (PCASL) sequence in 49 first-episode patients (22.6 ± 5.2 years, 58% females) and 50 healthy controls (HCs) (22.3 ± 4.4 years, 63% females) at baseline and in 29 patients and 49 HCs after six weeks. RCBF in striatum and thalamus was estimated with a region-of-interest (ROI) approach. Psychopathology was assessed with the positive and negative syndrome scale.

RESULTS

Baseline rCBF in striatum and thalamus was not altered in the combined patient group compared with HCs, but female patients had lower striatal rCBF compared with male patients (p = 0.009). Treatment with a partial dopamine agonist increased rCBF significantly in striatum (p = 0.006) in the whole patient group, but not significantly in thalamus. Baseline rCBF in nucleus accumbens was negatively associated with improvement in positive symptoms (p = 0.046), but baseline perfusion in whole striatum and thalamus was not related to treatment outcome.

CONCLUSIONS

The findings suggest that striatal perfusion is increased by partial dopamine agonism and decreased in female patients prior to first treatment. This underlines the importance of treatment effects and sex differences when investigating the neurobiology of psychosis.

Stroke Severity in Ischemic Stroke Patients with a History of Diastolic Blood Pressure Treated in a Telestroke Network

Background: The relationship between diastolic blood pressure (DBP), risk factors, and stroke severity in acute ischemic stroke (AIS) patients treated in a telestroke network is not fully understood. The present study aims to determine the effect of risk factors on stroke severity in AIS patients with a history of elevated DBP. Material and Methods: We retrospectively analyzed data on stroke severity for AIS patients treated between January 2014 and June 2016 treated in the PRISMA Health telestroke network. Data on the severity of stroke on admission were evaluated using NIHSS scores ≤7 for reduced, and >7 for increased, stroke severity. DBP was stratified as ≤80 mmHg for reduced DBP and >80 mmHg for elevated DBP. The study’s primary outcomes were risk factors associated with improving neurologic functions or reduced stroke severity and deteriorating neurologic functions or increased stroke severity. The associations between risk factors and stroke severity for AIS with elevated DBP were determined using multi-level logistic and regression models. Results: In the adjusted analysis, AIS patients with a DBP ≤ 80 mmHg, obesity (OR = 0.388, 95% Cl, 0.182−0.828, p = 0.014) was associated with reduced stroke severity, while an increased heart rate (OR = 1.025, 95% Cl, 1.001−1.050, p = 0.042) was associated with higher stroke severity. For AIS patients with a DBP > 80 mmHg, hypertension (OR = 3.453, 95% Cl, 1.137−10.491, p = 0.029), history of smoking (OR = 2.55, 95% Cl, 1.06−6.132, p = 0.037), and heart rate (OR = 1.036, 95% Cl, 1.009−1.064, p = 0.009) were associated with higher stroke severity. Caucasians (OR = 0.294, 95% Cl, 0.090−0.964, p = 0.002) and obesity (OR = 0.455, 95% Cl, 0.207−1.002, p = 0.05) were more likely to be associated with reduced stroke severity. Conclusions: Our findings reveal specific risk factors that can be managed to improve the care of AIS patients with elevated DBP treated in the telestroke network.

Longitudinal change in blood DNA epigenetic signature after smoking cessation

Cigarette smoking is associated with epigenetic changes that may be reversible following smoking cessation. Whole blood DNA methylation was evaluated in Framingham Heart Study Offspring (n = 169) and Third Generation (n = 30) cohort participants at two study visits 6 years apart and in Atherosclerosis Risk in Communities (ARIC) study (n = 222) participants at two study visits 20 years apart. Changes in DNA methylation (delta β values) at 483,565 cytosine-phosphate-guanine (CpG) sites and differentially methylated regions (DMRs) were compared between participants who were current, former, or never smokers at both visits (current-current, former-former, never-never, respectively), versus those who quit in the interim (current-former). Interim quitters had more hypermethylation at four CpGs annotated to AHRR, one CpG annotated to F2RL3, and one intergenic CpG (cg21566642) compared with current-current smokers (FDR < 0.02 for all), and two significant DMRs were identified. While there were no significant differentially methylated CpGs in the comparison of interim quitters and former-former smokers, 106 DMRs overlapping with small nucleolar RNA were identified. As compared with all non-smokers, current-current smokers additionally had more hypermethylation at two CpG sites annotated to HIVEP3 and TMEM126A, respectively, and another intergenic CpG (cg14339116). Gene transcripts associated with smoking cessation were implicated in immune responses, cell homoeostasis, and apoptosis. Smoking cessation is associated with early reversion of blood DNA methylation changes at CpG sites annotated to AHRR and F2RL3 towards those of never smokers. Associated gene expression suggests a role of longitudinal smoking-related DNA methylation changes in immune response processes.

Reduction in cerebral oxygen metabolism in subcortical regions may be a biomarker of cognitive decline in people living with human immunodeficiency virus

BACKGROUND AND PURPOSE

Regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO₂ ) in whole brain, white matter, gray matter and lenticular nuclei were studied in people living with human immunodeficiency virus (PLHIV) as well as HIV-associated neurocognitive disorder (HAND).

METHODS

Treatment-naïve PLHIV underwent neurocognitive assessment and magnetic resonance (MR) measurement of rCBF and rCMRO₂ with repeat after 12 months of antiretroviral therapy (ART). Age- and sex-matched controls underwent single MR measurements. Regional CBF and rCMRO₂ were compared amongst symptomatic, asymptomatic, normal HAND and controls using analysis of variance. Longitudinal analysis of HAND worsening (≥1 category) was assessed after 12 months of ART and correlated with rCBF and rCMRO₂ measured by MR imaging using the paired-sample t test.

RESULTS

Thirty PLHIV completed baseline and 12-month assessments (29 with rCMRO₂ measurement). At baseline HAND assessment, 13% had no cognitive impairment, 27% had asymptomatic neurocognitive impairment, 60% had mild neurocognitive disorder and none had HIV-associated dementia. At 12 months, 13% had no cognitive impairment, 20% had asymptomatic neurocognitive impairment, 50% had mild neurocognitive disorder and 17% had HIV-associated dementia. In those without HAND worsening (N = 21) rCMRO₂ remained stable and in those with HAND worsening (N = 8) rCMRO₂ measurement declined from baseline to 12 months in white matter (2.05 ± 0.40 to 1.73 ± 0.51, p = 0.03) and lenticular nuclei (4.32 ± 0.39 to 4.00 ± 0.51, p = 0.05).

CONCLUSIONS

In recently diagnosed PLHIV, no association was found between rCBF or rCMRO₂ and cognitive impairment at baseline. There was a reduction in rCMRO₂ in those with worsening of cognitive function at 12 months on ART. Reduction in rCMRO₂ may be a biomarker of cognitive decline in PLHIV.

Association of Early Adulthood 25-Year Blood Pressure Trajectories With Cerebral Lesions and Brain Structure in Midlife

IMPORTANCE

Midlife elevated blood pressure (BP) is an important risk factor associated with brain structure and function. Little is known about trajectories of BP that modulate this risk.

OBJECTIVE

To identify BP trajectory patterns from young adulthood to midlife that are associated with brain structure in midlife.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data of US adults from Coronary Artery Risk Development in Young Adults (CARDIA), a prospective longitudinal study of Black and White men and women (baseline age 18 to 30 years) examined up to 8 times over 30 years (1985-1986 to 2015-2016). There were 885 participants who underwent brain magnetic resonance imaging (MRI) in the 25th or 30th year examinations. Analyses were conducted November 2019 to December 2020.

EXPOSURES

Using group-based trajectory modeling, 5 25-year BP trajectories for 3 BP traits were identified in the total CARDIA cohort of participants with 3 or more BP measures, which were then applied to analyses of the subset of 853 participants in the Brain MRI substudy. Mean arterial pressure (MAP) was examined as an integrative measure of systolic and diastolic BP. With linear regression, the associations of the BP trajectories with brain structures were examined, adjusting sequentially for demographics, cardiovascular risk factors, and antihypertensive medication use.

MAIN OUTCOMES AND MEASURES

Brain MRI outcomes include total brain, total gray matter, normal-looking and abnormal white matter volumes, gray matter cerebral blood flow, and white matter fractional anisotropy.

RESULTS

Brain MRI analyses were conducted on 853 participants (mean [SD] age, 50.3 [3.6] years; 399 [46.8%] men; 354 [41.5%] Black and 499 [58.5%] White individuals). The MAP trajectory distribution was 187 individuals (21.1%) with low-stable, 385 (43.5%) with moderate-gradual, 71 (8.0%) with moderate-increasing, 204 (23.1%) with elevated-stable, and 38 (4.3%) with elevated-increasing. Compared with the MAP low-stable trajectory group, individuals in the moderate-increasing and elevated-increasing groups were more likely to have higher abnormal white matter volume (moderate: β, 0.52; 95% CI, 0.23 to 0.82; elevated: β, 0.57; 95% CI, 0.19 to 0.95). Those in the MAP elevated-increasing group had lower gray matter cerebral blood flow (β, -0.42; 95% CI, -0.79 to -0.05) after adjusting for sociodemographics and cardiovascular risk factors. After adjustment for antihypertensive medication use, the difference was consistent for abnormal white matter volume, but results were no longer significant for gray matter cerebral blood flow.

CONCLUSIONS AND RELEVANCE

Among young adults with moderate to high levels of BP, a gradual increase in BP to middle-age may increase the risk in diffuse small vessel disease and lower brain perfusion.

Factors affecting brain structure in smoking-related diseases: Chronic Obstructive Pulmonary Disease (COPD) and coronary artery disease

Background

Changes in brain structure and cognitive decline occur in Chronic Obstructive Pulmonary Disease (COPD). They also occur with smoking and coronary artery disease (CAD), but it is unclear whether a common mechanism is responsible.

Methods

Brain MRI markers of brain structure were tested for association with disease markers in other organs. Where possible, principal component analysis (PCA) was used to group markers within organ systems into composite markers. Univariate relationships between brain structure and the disease markers were explored using hierarchical regression and then entered into multivariable regression models.

Results

100 participants were studied (53 COPD, 47 CAD). PCA identified two brain components: brain tissue volumes and white matter microstructure, and six components from other organ systems: respiratory function, plasma lipids, blood pressure, glucose dysregulation, retinal vessel calibre and retinal vessel tortuosity. Several markers could not be grouped into components and were analysed as single variables, these included brain white matter hyperintense lesion (WMH) volume. Multivariable regression models showed that less well organised white matter microstructure was associated with lower respiratory function (p = 0.028); WMH volume was associated with higher blood pressure (p = 0.036) and higher C-Reactive Protein (p = 0.011) and lower brain tissue volume was associated with lower cerebral blood flow (p<0.001) and higher blood pressure (p = 0.001). Smoking history was not an independent correlate of any brain marker.

Conclusions

Measures of brain structure were associated with a range of markers of disease, some of which appeared to be common to both COPD and CAD. No single common pathway was identified, but the findings suggest that brain changes associated with smoking-related diseases may be due to vascular, respiratory, and inflammatory changes.

Body weight variability and cancer incidence in men aged 40 years and older-Korean National Insurance Service Cohort

Repeated weight fluctuation has been proposed as a potential risk factor for increasing morbidity and mortality including cancer. We aimed to investigate the association between body weight variability (BWV) and all cancer and site-specific cancer incidence and the impact of smoking on these associations. A total of 1,759,848 cancer-free male subjects who had their weight measured at least 5 times from the National Health Insurance Service-Health Screening Cohort from 2002 to 2011 were included and followed up until 2015. BWV was defined as the average absolute difference between successive values (ASV). The risk of cancer and site-specific cancer from BWV was identified using Cox proportional hazards regression analysis using hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for potential confounders including weight, and stratified analysis was also conducted according to smoking status. During the 7,015,413 person-years of follow-up, 11,494 patients (0.65%) developed new-onset cancers. BWV was associated with a higher risk of all cancers after adjustment for confounders. The highest BWV quintile group compared to the lowest had greater risks of all cancers and site-specific cancers including lung, liver, and prostate cancer (HR 1.22, 95% CI 1.15–1.30; HR 1.22, 95% CI 1.07–1.39; HR 1.46, 95% CI 1.19–1.81; HR 1.36, 95% CI 1.15–1.62, in all cancers, lung, liver and prostate cancer, respectively). Due to small number of cancer occurrence, the risk of kidney cancer was increased, but statistically insignificant (HR 1.38, 95% CI 0.91–2.10). Similar results were observed in noncurrent smokers. However, in current smokers, the risks of all cancers and only prostate cancer were significantly increased in the highest BWV quintile group (HR 1.19, 95% CI 1.09–1.31; HR 1.51, 95% CI 1.08–2.11). The risk of kidney cancer also increased in this group, although the finding was not statistically significant (HR 1.77, 95% CI 0.87–3.63) This study suggested BWV is an independent risk factor for cancer in men, especially in lung, liver, and prostate cancer, but evidence was weaker in kidney cancer. This association remained significant only in prostate cancer in current smokers.

Carotid Intima-Media Thickness and Markers of Brain Health in a Biracial Middle-Aged Cohort: CARDIA Brain MRI Sub-study

BACKGROUND

We investigated whether carotid intima-media thickness is associated with measures of cerebral blood flow (CBF), white matter hyperintensities, and brain volume in a biracial cohort of middle-aged individuals.

METHODS

We performed a cross-sectional cohort study based on data from a multicenter, population-based study Coronary Artery Risk Development in Young Adults. Using linear and logistic regression, we estimated the association of the composite intima-media thickness measured in three segments of carotid arteries (common carotid artery, carotid artery bulb, and internal carotid artery) with volume (cm3) and CBF (mL/100 g/min) in the total brain and gray matter as well as volume of white matter hyperintensities (cm3).

RESULTS

In the analysis, 461 participants (54% women, 34% African Americans) were included. Greater intima-media thickness was associated with lower CBF in gray matter (β=-1.36; p = .04) and total brain (β=-1.26; p = .04), adjusting for age, sex, race, education, and total brain volume. The associations became statistically nonsignificant after further controlling for cardiovascular risk factors. Intima-media thickness was not associated with volumes of total brain, gray matter, and white matter hyperintensities.

CONCLUSIONS

This study suggests that lower CBF in middle age is associated with markers of atherosclerosis in the carotid arteries. This association may reflect early long-term exposure to traditional cardiovascular risk factors. Early intervention on atherosclerotic risk factors may modulate the trajectory of CBF as people age and develop brain pathology.

Cigarette smoking and cerebral blood flow in a cohort of middle-aged adults

Cigarette smoking increases cerebral blood flow. Both nicotine and carbon monoxide contribute to the flow increase. Due to carbon monoxide’s high affinity to hemoglobin and slow clearance from the blood, the effect lasts for hours. Nicotine also stays in the organism for some hours. This immediate effect of smoking may explain a recently observed higher cerebral blood flow in current-smokers as compared to former-smokers.