Castillo, Pablo R

Background and Purpose— The apnea-hypopnea index (AHI) is associated with cerebral small vessel disease (cSVD), but pathogenesis of this association is elusive. We aimed to assess the effect of nighttime heart rate variability (HRV)—as a proxy of sympathetic upregulation—on the aforementioned association. Methods— Atahualpa residents aged ≥60 years undergoing brain magnetic resonance imaging, polysomnography, and 24-hour Holter monitoring (N=176) were included. The presence of moderate-to-severe white matter hyperintensities, deep cerebral microbleeds, lacunar infarcts, and >10 enlarged basal ganglia perivascular spaces were added for estimating the cSVD score. Interaction models were fitted to assess the effect modification of nighttime HRV in the association between the AHI and the cSVD score, and mediation analysis was utilized to assess the proportion of total effect by nighttime HRV on this association. Results— Generalized linear models showed a significant association between the AHI and the cSVD score ( P =0.025), as well as a significant inverse association between nighttime HRV and the cSVD score ( P =0.002), but no association between daytime HRV and the cSVD score ( P =0.097). Interaction models showed a significant interaction of nighttime HRV on the association between AHI and the cSVD score ( P =0.001), and mediation analysis found that the percent of total effect between AHI and cSVD score mediated by HRV was 30.8%. Predictive marginal means of the cSVD score were highly significant when the 10th percentile of nighttime HRV was compared across categories of 10th and 90th percentiles of the AHI (cSVD score margins, 0.61 [95% CI, 0.37–0.86] versus 1.67 [95% CI, 1.26–2.09]). Contour plots showed the effect of nighttime (but not daytime) HRV on the association between AHI and the cSVD score. Conclusions— This study shows an important effect of nighttime HRV on the association between the AHI and the cSVD score and provides further support for the role of sympathetic overactivity on this association.

There is limited information on participants’ adherence and reasons for declining consent in observational cohort studies conducted in remote rural communities. We aimed at sharing lessons learned during the Atahualpa Project, a population-based cohort study conducted in a rural Ecuadorian village. Atahualpa residents aged ≥40 years identified during door-to-door surveys who signed a consent form were enrolled. Annual surveys were conducted to assess the number of participants who moved out of the village, as well as those who died, declined consent, and newly entered the study. Reasons for declining consent were tabulated. Abstracted data included age, sex, education, disability, time between enrollment and declining consent, and reasons for withdrawal. We also counted participants who, despite expressing their willingness to continue in the study, refused specific procedures. After five years of follow-up, 54 (6.3%) of 863 enrolled individuals declined consent. Increasing age and disability had no impact on declining consent. In contrast, refusal was higher among relatives or neighbors of a given participant declining consent. Most people who declined consent did so after one or two years of enrollment. Less than 20% of enrolled individuals refused certain procedures. “Fear of the needle” was the most frequent reason for refusing blood tests, and common reasons for declining complimentary exams were lack of interest and time constraints. Cohort retention in the Atahualpa Project is high. Main reasons for this adherence include adequate selection of the village, detailed planning of procedures, assurance of sponsorship, and field personnel who continuously engage with study participants. This trial is registered with NCT01627600.

ABSTRACT Background: There is no information on the prevalence of symptoms related to neurotoxicity among carpenters working in underserved populations. To assess the magnitude of the problem, we conducted a population-based study in Atahualpa, a rural Ecuadorian village, where most men work as carpenters under poor safety conditions. Methods: All men aged 40–75 years living in Atahualpa were identified during a door-to-door survey and evaluated with a general demographic questionnaire, the Q16 questionnaire, the depression axis of the Depression Anxiety Stress Scale-21, and the Montreal Cognitive Assessment (MoCA). Results: Among 230 participants, 63% were carpenters. Seventy participants (30%) had a positive Q16 questionnaire (≥6 points), which suggested neurotoxicity. In a logistic regression model adjusted for age, education, alcohol intake, symptoms of depression, and MoCA score, the proportion of Q16 positive persons was 39.1% for carpenters and 15.9% for noncarpenters (odds ratio: 3.53, 95% confidence interval: 1.75–7.15, P < 0.0001). In a generalized linear model, adjusted mean scores in the Q16 questionnaire were 4.9 for carpenters and 3.6 for noncarpenters (β: 1.285, standard error: 0.347, P < 0.0001). There was no correlation between scores in the Q16 questionnaire and the MoCA (Pearson correlation coefficient = −0.02), and the only significant covariate in the multivariate linear model was age, with every 10 years of age difference contributing 0.64 points in the Q16 questionnaire. Conclusion: This study shows a high prevalence of symptoms associated with neurotoxicity among carpenters after adjusting for a number of confounders. Long-term exposure to toxic solvents is the most likely explanation to this finding.

ABSTRACT Community-dwellers aged ≥ 60 years enrolled in the Atahualpa Project underwent brain MRI and were interviewed with the Pittsburgh Sleep Quality Index. Of 290 participants, 94 (32%) had poor sleep quality and 143 (49%) had global cortical atrophy (GCA). In a logistic regression model (adjusted for demographics, cardiovascular risk factor, severe edentulism, symptoms of depression, the MoCA score, and neuroimaging signatures of cerebrovascular damage), poor sleep quality was associated with GCA (p=0.004). A multivariate probability model showed that the probability of moderate-to-severe GCA significantly increased in individuals with poor sleep quality aged ≥ 67 years. This study provides evidence for an association between poor sleep quality and GCA in older adults and the important interaction of age in this association.

The effect of fish consumption on blood pressure is controversial. The authors measured blood pressure and calculated oily fish servings per week in 677 community‐dwellers aged 40 years and older living in rural coastal Ecuador. Using regression models with linear splines, the authors evaluated whether dietary fish intake was related to blood pressure levels, after adjusting for relevant confounders. Mean oily fish consumption was 9.1±5.6 servings per week. There was a nonlinear relationship between systolic pressure and fish servings. In the group of individuals consuming up to five servings per week, each serving significantly reduced systolic pressure by 2.3 mm Hg (P=.020). Any extra serving provided no further effects. The study shows an inverse relationship between oily fish consumption and systolic pressure. Currently recommended amounts of dietary oily fish intake per week (1–2 servings) might be insufficient to exert beneficial effects of fish in the control of blood pressure.

ABSTRACTPurposeTo assess the role of temporal bone characteristics in transcranial Doppler (TCD) insonation failures in Amerindians living in rural Ecuador.MethodsWe evaluated thickness and texture of temporal bones in community‐dwelling Amerindians ≥65 years old undergoing TCD. Using receiver operator characteristics curve analysis and generalized estimating equations, we investigated factors associated with insonation failures.ResultsOf 65 participants (mean age 74.7 ± 6.7 years, 60% women), 32 (49%) had uni‐ or bilateral insonation failure through temporal windows. Considering temporal bones independently, 57 of 130 (44%) had poor insonation. Mean thickness was higher (4.7 ± 1.2 versus 2.7 ± 0.9, p < 0.0001), and texture more often heterogeneous (93% versus 22%, p < 0.0001) in bones with poor acoustic windows. Thickness, better predicting poor insonation, was ≥3.6 mm if used alone, and ≥2.7 mm if used together with heterogeneous texture. For every millimeter of increase in thickness, subjects were 2.9 times more likely to have insonation failures. Per se, heterogeneous texture increased by 3.2 times the odds for poor insonation. In all models, being woman increased the odds for poor insonation by six to nine times.ConclusionsTemporal bone thickness and texture are independent predictors of TCD insonation failure in Amerindians. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 44:55–60, 2016

ABSTRACT Background: Diagnosis of cerebral small vessel disease (SVD) is a challenge in remote areas where magnetic resonance imaging (MRI) is not available. Hospital-based studies in high-risk or stroke patients have found an association between the pulsatility index (PI) of intracranial arteries - as derived from transcranial Doppler (TCD) - and white matter hyperintensities (WMH) of presumed vascular origin. We aimed to assess the reliability of cerebral pulsatility indices to identify candidates for MRI screening in population-based studies assessing prevalence of SVD. Methods: A representative sample of stroke-free Atahualpa residents aged ≥65 years investigated with MRI underwent TCD. Using generalized linear models, we evaluated whether the PI of major intracranial arteries correlate with WMH (used as a proxy of diffuse SVD), after adjusting for demographics and cardiovascular risk factors. Results: Out of 70 participants (mean age 70.6 ± 4.6 years, 57% women), 28 (40%) had moderate-to-severe WMH. In multivariate models, there were no differences across categories of WMH in the mean PI of middle cerebral arteries (1.10 ± 0.16 vs. 1.22 ± 0.24, β: 0.065, 95% confidence interval (CI): −0.084-0.177, P = 0.474) or vertebrobasilar arteries (1.11 ± 0.16 vs. 1.29 ± 0.27, β: 0.066, 95% CI: −0.0024-0.156, P = 0.146). Conclusions: Cerebral PI should not be used to identify candidates for MRI screening in population-based studies assessing the burden of SVD.

Background. Little is known on the prevalence of peripheral artery disease (PAD) in developing countries.Study design. Population-based study in Atahualpa. InPhase I, the Edinburgh claudication questionnaire (ECQ) was used for detection of suspected symptomatic PAD; persons with a negative ECQ but a pulse pressure ≥65 mmHg were suspected of asymptomatic PAD. InPhase II, the ankle-brachial index will be used to test reliability of screening instruments and to determine PAD prevalence. InPhase III, participants will be followed up to estimate the relevance of PAD as a predictor of vascular outcomes.Results. DuringPhase I, 665 Atahualpa residents aged ≥40 years were enrolled (mean age: 59.5 ± 12.6 years, 58% women). A poor cardiovascular health status was noticed in 464 (70%) persons of which 27 (4%) had a stroke and 14 (2%) had ischemic heart disease. Forty-four subjects (7%) had suspected symptomatic PAD and 170 (26%) had suspected asymptomatic PAD. Individuals with suspected PAD were older, more often women, and had a worse cardiovascular profile than those with nonsuspected PAD.Conclusions. Prevalence of suspected PAD in this underserved population is high. Subsequent phases of this study will determine whether prompt detection of PAD is useful to reduce the incidence of catastrophic vascular diseases in the region.