Familial aggregation of tobacco use behaviors among Amish men

Depression, stress and regional cerebral blood flow

Decreased cerebral blood flow (CBF) may be an important mechanism associated with depression. In this study we aimed to determine if the association of CBF and depression is dependent on current level of depression or the tendency to experience depression over time (trait depression), and if CBF is influenced by depression-related factors such as stressful life experiences and antidepressant medication use. CBF was measured in 254 participants from the Amish Connectome Project (age 18-76, 99 men and 154 women) using arterial spin labeling. All participants underwent assessment of symptoms of depression measured with the Beck Depression Inventory and Maryland Trait and State Depression scales. Individuals diagnosed with a unipolar depressive disorder had significantly lower average gray matter CBF compared to individuals with no history of depression or to individuals with a history of depression that was in remission at time of study. Trait depression was significantly associated with lower CBF, with the associations strongest in cingulate gyrus and frontal white matter. Use of antidepressant medication and more stressful life experiences were also associated with significantly lower CBF. Resting CBF in specific brain regions is associated with trait depression, experience of stressful life events, and current antidepressant use, and may provide a valuable biomarker for further studies.

Cerebral blood flow and cardiovascular risk effects on resting brain regional homogeneity

Regional homogeneity (ReHo) is a measure of local functional brain connectivity that has been reported to be altered in a wide range of neuropsychiatric disorders. Computed from brain resting-state functional MRI time series, ReHo is also sensitive to fluctuations in cerebral blood flow (CBF) that in turn may be influenced by cerebrovascular health. We accessed cerebrovascular health with Framingham cardiovascular risk score (FCVRS). We hypothesize that ReHo signal may be influenced by regional CBF; and that these associations can be summarized as FCVRS→CBF→ReHo. We used three independent samples to test this hypothesis. A test-retest sample of N = 30 healthy volunteers was used for test-retest evaluation of CBF effects on ReHo. Amish Connectome Project (ACP) sample (N = 204, healthy individuals) was used to evaluate association between FCVRS and ReHo and testing if the association diminishes given CBF. The UKBB sample (N = 6,285, healthy participants) was used to replicate the effects of FCVRS on ReHo. We observed strong CBF→ReHo links (p<2.5 × 10^-3) using a three-point longitudinal sample. In ACP sample, marginal and partial correlations analyses demonstrated that both CBF and FCVRS were significantly correlated with the whole-brain average (p<10^-6) and regional ReHo values, with the strongest correlations observed in frontal, parietal, and temporal areas. Yet, the association between ReHo and FCVRS became insignificant once the effect of CBF was accounted for. In contrast, CBF→ReHo remained significantly linked after adjusting for FCVRS and demographic covariates (p<10^-6). Analysis in N = 6,285 replicated the FCVRS→ReHo effect (p = 2.7 × 10^-27). In summary, ReHo alterations in health and neuropsychiatric illnesses may be partially driven by region-specific variability in CBF, which is, in turn, influenced by cardiovascular factors.

Physical health conditions of the Amish and intervening social mechanisms: an exhaustive narrative review

As an ethnic religion, the Amish are of interest to population health researchers due to a distinctive health profile arising from ethnic attributes, including a closed genetic pool and shared culture that shapes lifestyle practices. Amish-focused health research both furthers our knowledge of health conditions by comparing Amish with non-Amish and assists health practitioners in serving this rapidly growing population. Amish health research, now representing approximately a quarter of all Amish-focused publications, is in need of review, to the end of strengthening this knowledge body's coherence, clarifying research directions, and identifying knowledge gaps, lapses, and stagnations. Herein, we synthesize and discuss Amish physical health conditions research, both the population's distinctive health profile and mechanisms shaping this profile. Specifically, we summarize research addressing BMI, physical activity, and body image; diet and supplements; cancer; cardiovascular conditions; communicable diseases; immunity; sleep; genetic disorders; tobacco and alcohol use; periodontal conditions; traumatic injuries; natural treatments for burns; fertility; and sexually transmitted diseases. In reflection, we raise questions about the nature of intervening mechanisms shaping the Amish health profile, the strange omission of several common independent variables commonly used when studying other ethnic groups' health, several recurring methodological complications, and public health policy considerations.

Research Trends in Amish Population Health, a Growing Literature about a Growing Rural Population

The Amish are an endogamous rural population experiencing rapid growth; consequently, they have attracted the attention of population health researchers and service providers. With approximately one quarter of all Amish studies publications now devoted to population health (n=246), the time is ripe to review research trends. Using bibliometric measures, we map the genealogy, influence, and configuration of Amish health publications. Amish population health research has (1) a health culture-focused core with clusters representing social science and health practice, (2) peripheral clusters addressing health conditions-mental, physical, and injury/safety-and (3) several clusters straddling both. We identify fruitful interdisciplinary studies and recommend researchers investigating health culture and conditions seek ways to integrate their research agendas. This article represents a pivot-point for Amish population health research, for it provides a first-ever bibliometric mapping, allowing researchers to more easily locate their work within the literature and identify opportunities for interdisciplinary collaborations.

Lipid Metabolism, Abdominal Adiposity, and Cerebral Health in the Amish

OBJECTIVE

To assess the association between peripheral lipid/fat profiles and cerebral gray matter (GM) and white matter (WM) in healthy Old Order Amish (OOA).

METHODS

Blood lipids, abdominal adiposity, liver lipid contents, and cerebral microstructure were assessed in OOA (N = 64, 31 males/33 females, ages 18-77). Orthogonal factors were extracted from lipid and imaging adiposity measures. GM assessment used the Human Connectome Project protocol to measure whole-brain average cortical thickness. Diffusion-weighted imaging was used to derive WM fractional anisotropy and kurtosis anisotropy measurements.

RESULTS

Lipid/fat measures were captured by three orthogonal factors explaining 80% of the variance. Factor one loaded on cholesterol and/or low-density lipoprotein cholesterol measurements; factor two loaded on triglyceride/liver measurements; and factor three loaded on abdominal fat measurements. A two-stage regression including age/sex (first stage) and the three factors (second stage) examined the peripheral lipid/fat effects. Factors two and three significantly contributed to WM measures after Bonferroni corrections (P < 0.007). No factor significantly contributed to GM. Blood pressure (BP) inclusion did not meaningfully alter the lipid/fat-WM relationship.

CONCLUSIONS

Peripheral lipid/fat indicators were significantly and negatively associated with cerebral WM rather than with GM, independent of age and BP level. Dissecting the fat/lipid components contributing to different brain imaging parameters may open a new understanding of the body-brain connection through lipid metabolism.

Gender differences in first and secondhand smoke exposure, spirometric lung function and cardiometabolic health in the old order Amish: A novel population without female smoking

Due to their relatively homogeneous lifestyle and living environment, the Amish offer a novel opportunity to study the health associations of tobacco smoke exposure, particularly secondhand smoke. We hypothesized that secondhand smoke exposure is associated with worse pulmonary and cardiometabolic health. We examined cross-sectional data on 3568 Amish study participants, including tobacco use and secondhand smoke exposure from family members included in the study. Thirty-four percent of Amish men reported ever smoking. Of this proportion, 64% used cigars, 46% cigarettes, and 21% pipes. Less than 1% of women reported ever smoking. Smoking was associated with lower spirometric lung function, higher body mass index, lower HDL cholesterol, higher heart rate, lower ankle-brachial index, and larger aortic diameter in men. A greater number of sources of secondhand smoke exposure (defined from the total of spouses, parents, and siblings who smoke) was associated with higher body mass index (p = 0.03) and with higher fasting glucose in men (p = 0.01), but not in women (p = 0.007 for sex*secondhand smoke interaction). Secondhand smoke exposure was also associated with reduced HDL cholesterol only in women (p = 0.002) and a lower heart rate only in men (p = 0.006). Smoking habits among the Old Order Amish are notable for the absence of female participation and a high proportion of cigar and pipe use. Smoking is associated with decreased spirometric indices of lung function and increased cardiovascular risk in this population and secondhand smoke exposure is associated with a greater burden of risk factors for cardiovascular disease. Sex differences in correlations could reflect differences in exposure patterns, mechanisms, or susceptibilities.

Social impacts on adult use of tobacco: findings from the International Tobacco Control Project India, Wave 1 Survey

BACKGROUND

Social impacts on tobacco use have been reported but not well quantified. This study investigated how strongly the use of smoked and smokeless tobacco may be influenced by other users who are close to the respondents.

METHODS

The International Tobacco Control Project (TCP), India, used stratified multistage cluster sampling to survey individuals aged ≥15 years in four areas of India about their tobacco use and that of their close associates. The present study used logistic regression to calculate odds ratios (ORs) for tobacco use for each type of close associate.

RESULTS

Among the 9780 respondents, tobacco use was significantly associated with their close associates' (father's, mother's, friends', spouse's) tobacco use in the same form. After adjusting for confounding variables, women smokers were nine times more likely to have a mother who ever smoked (OR: 9.0; 95% confidence interval [CI]: 3.3-24.7) and men smokers five times more likely (OR: 5.4; 95% CI: 2.1-14.1) than non-smokers. Men smokers were seven times more likely to have close friends who smoked (OR: 7.2; 95% CI: 5.6-9.3). Users of smokeless tobacco (SLT) were five times more likely to have friends who used SLT (OR: 5.3; 95% CI: 4.4-6.3 [men]; OR: 5.0; 95% CI: 4.3-5.9 [women]) and four times more likely to have a spouse who used SLT (OR: 4.1; 95% CI: 3.0-5.8 [men]; OR: 4.3; 95% CI: 3.6-5.3 [women]), than non-users. The ORs for the association of the individuals' tobacco use, whether smoked or smokeless, increased with the number of close friends using it in the same form.

CONCLUSION

The influence of family members and friends on tobacco use needs to be appropriately addressed in tobacco-control interventions.

Nicotine withdrawal

An aversive abstinence syndrome manifests 4-24 h following cessation of chronic use of nicotine-containing products. Symptoms peak on approximately the 3rd day and taper off over the course of the following 3-4 weeks. While the severity of withdrawal symptoms is largely determined by how nicotine is consumed, certain short nucleotide polymorphisms (SNPs) have been shown to predispose individuals to consume larger amounts of nicotine more frequently--as well as to more severe symptoms of withdrawal when trying to quit. Additionally, rodent behavioral models and transgenic mouse models have revealed that specific nicotinic acetylcholine receptor (nAChR) subunits, cellular components, and neuronal circuits are critical to the expression of withdrawal symptoms. Consequently, by continuing to map neuronal circuits and nAChR subpopulations that underlie the nicotine withdrawal syndrome--and by continuing to enumerate genes that predispose carriers to nicotine addiction and exacerbated withdrawal symptoms--it will be possible to pursue personalized therapeutics that more effectively treat nicotine addiction.

The nicotinic cholinergic system function in the human brain

Research on the nicotinic cholinergic system function in the brain was previously mainly derived from animal studies, yet, research in humans is growing. Up to date, findings allow significant advances on the understanding of nicotinic cholinergic effects on human cognition, emotion and behavior using a range of functional brain imaging approaches such as pharmacological functional magnetic resonance imaging or positron emission tomography. Studies provided insights across various mechanistic psychological domains using different tasks as well as at rest in both healthy individuals and patient populations, with so far partly mixed results reporting both enhancements and decrements of neural activity related to the nicotinic cholinergic system. Moreover, studies on the relation between brain structure and the nicotinic cholinergic system add important information in this context. The present review summarizes the current status of human brain imaging studies and presents the findings within a theoretical and clinical perspective as they may be useful not only for an advancement of the understanding of basic nicotinic cholinergic-related mechanisms, but also for the development and integration of psychological and pharmacological treatment approaches. Patterns of functional neuroanatomy and neural circuitry across various cognitive and emotional domains may be used as neuropsychological markers of mental disorders such as addiction, Alzheimer's disease, Parkinson disease or schizophrenia, where nicotinic cholinergic system changes are characteristic. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.