Reasons for Declining Consent in a Population-Based Cohort Study Conducted in a Rural South American Community

Cognitive performance and all-cause mortality in community dwellers of Amerindian ancestry living in rural Ecuador: A population-based, longitudinal prospective study

OBJECTIVE

There is limited information on mortality risk in individuals with cognitive impairment living in rural Latin America. In this study, we assess the association between cognitive impairment and all-cause mortality in adults of Amerindian ancestry living in rural Ecuador.

PATIENTS AND METHODS

Middle-aged and older adults enrolled in the population-based Three Villages Study cohort were followed prospectively in order to estimate mortality risk according to their baseline cognitive performance as determined by the Montreal Cognitive Assessment (MoCA). Results were adjusted for demographics, level of education, traditional cardiovascular risk factors, symptoms of depression, severe tooth loss, and oily fish intake (factors previously associated with mortality in the study population).

RESULTS

Analysis included 1022 individuals followed for an average of 7.8 ± 3.4 years. Mean MoCA score was 21.2 ± 5.4 points (median: 22 points), with 334 (32.7%) individuals showing cognitive impairment, as evidenced by a MoCA score ≤ 19 points (the cutoff for poor cognitive performance based on previous studies in the same population). A total of 150 (14.7%) individuals died during the follow-up. Crude mortality rate was 2.87 per 100 person-years (95% C.I.: 2.08 - 3.96). For individuals with normal cognition, the mortality rate was 1.21 (95% C.I.: 0.92 - 1.50) while for those with cognitive impairment the rate increased to 3.48 (95% C.I.: 2.73 - 4.23). A multivariate Cox-proportional hazards model, confirmed that individuals with cognitive impairment had a significantly higher mortality risk than those without cognitive impairment (HR: 1.52; 95% C.I.: 1.05 - 2.18).

CONCLUSIONS

Cognitive impairment is associated with mortality in the study population.

Incidence of Adult-Onset Epilepsy and the Contributory Role of Neurocysticercosis in a Five-Year, Population-Based, Prospective Study in Rural Ecuador

This prospective cohort study aimed to assess incidence and etiology of adult-onset epilepsy in previously seizure-free Atahualpa residents aged ≥ 20 years. Persons with adult-onset epilepsy occurring over 5 years were identified from annual door-to-door surveys and other overlapping sources. Those who emigrated or declined consent were excluded at the administrative censoring date of the last survey when these subjects were interviewed. Persons who died and those who developed incident epilepsy were censored at the time of these outcomes. Poisson regression models adjusted for demographics, education, alcohol intake, and the length of observation time, were used to estimate annual adult-onset epilepsy incidence rate ratio and cumulative incidence. Systematic neuroimaging screening was offered to participants to get insights on the etiology of epilepsy. Individuals enrolled in this cohort (N = 1,480) contributed to 6,811.6 years of follow-up. Seventeen developed incident adult-onset epilepsy, for an annual incident rate of 249.2 per 100,000 persons-year (95% CI: 130.7-367.7). Cumulative incidence was 1,245.9 per 100,000 persons (95% CI: 653.7-1,838.3) after a mean of 4.6 (SE: 0.06) years of follow-up. Six persons with incident epilepsy had neurocysticercosis (35%). Individuals with neurocysticercosis were six times more likely to develop adult-onset epilepsy than those without this disease (IRR: 6.01; 95% CI: 2.16-16.7), after adjusting for relevant covariates. The attributable fraction of incident adult-onset epilepsy due to neurocysticercosis was 30.9% (95% CI: 25.6-46.2%). This rural Ecuadorian population has a high incidence of adult-onset epilepsy, with neurocysticercosis being an important contributory cause.

Risk for Subsequent SARS-CoV-2 Infection and Severe COVID-19 Among Community-Dwellers With Pre-Existing Cervicocephalic Atherosclerosis: A Population-Based Study

BACKGROUND

COVID-19 patients may develop atherosclerosis-related complications. Whether a proportion of these patients already had asymptomatic cervicocephalic atherosclerosis before SARS-CoV-2 infection is not known. This study assessed whether pre-existing cervicocephalic atherosclerosis increased the susceptibility to SARS-CoV-2 infection or resulted in more severe or fatal COVID-19.

METHODS

Individuals enrolled in the Atahualpa Project cohort who received head CT (for assessing carotid siphon calcifications) and B-mode ultrasounds (for measurement of the carotid intima-media thickness) prior to the pandemic were eligible for this study. Among this cohort, those who also received serological tests for detection of SARS-CoV-2 antibodies and clinical evaluations for assessment of COVID-19 severity were enrolled. Multivariate logistic regression and exposure-effect models were fitted to assess the association between pre-existing atherosclerosis biomarkers, and SARS-CoV-2 seropositivity and COVID-19 severity.

RESULTS

Overall, 154 of 519 study participants (30%) had evidence of cervicocephalic atherosclerosis. A total of 325 (63%) individuals became SARS-CoV-2 positive, and 65 (23.5%) of seropositive individuals had severe or fatal COVID-19. The risk of SARS-CoV-2 seropositive status did not differ across individuals with and without atherosclerosis biomarkers (P = .360). Likewise, seropositive individuals with pre-existing atherosclerosis were not more prone to develop severe or fatal COVID-19 than those without evidence of atherosclerosis (P = .274). Average estimated exposure effects of pre-existing cervicocephalic atherosclerosis versus no atherosclerosis over SARS-CoV-2 seropositivity and COVID-19 severity were not significant.

CONCLUSIONS

Pre-existing cervicocephalic atherosclerosis does not increase the risk of acquiring SARS-CoV-2 infection nor the severity of COVID-19 among seropositive individuals.

Hypertensive Retinopathy and All-Cause Mortality in Older Adults of Amerindian Ancestry. A Population-based Longitudinal Prospective Study

Introduction

Hypertensive retinopathy (HTRP) predicts all-cause mortality in Asian and Caucasian populations. However, little is known about HTRP impact in other ethnic groups.

Aim

We sought to estimate the mortality risk according to HTRP severity in older adults of Amerindian ancestry living in rural Ecuador.

Methods

This prospective study enrolled individuals aged ≥ 60 years with baseline blood pressure ≥ 120/≥ 80 mmHg from the ongoing Atahualpa Project cohort who received retinal photographs (for HTRP grading) and a brain MRI. We ascertained all-cause mortality after a mean of 5.2 ± 1.2 years of follow-up. Cox-proportional hazards models adjusted for demographics, cardiovascular risk factors, neuroimaging signatures of cerebral small vessel disease, blood pressure determinations during follow-up and incident strokes, were obtained to estimate mortality risk according to HTRP severity.

Results

Analysis included 236 participants (mean age 69.3 ± 7.3 years). HTRP Grade 2 or higher was determined in 42 (18%) individuals. Fifty participants (21%) died during the follow-up, resulting in an overall unadjusted crude mortality rate of 4.1 per 100 person-years. Mortality rate in subjects with HTRP Grade 2 or higher was 7.2 and in those with no HTRP or Grade 1 only was 3.4 per 100 person-years. An adjusted Cox-proportional hazard model showed that individuals with HTRP Grade 2 or higher maintained a greater than two-fold mortality risk (HR 2.08; 95% C.I. 1.04–4.15; p = 0.038) when compared to those with no HTRP or Grade 1 only.

Conclusion

Study results show that HTRP severity predicts mortality in this population of older adults.

Body Composition in Community-Dwelling Older Adults Before and After SARS-CoV-2 Infection: A Longitudinal Prospective Study in a Rural Village Struck by the Pandemic

Background:

Information on the body composition of inhabitants of remote communities during the SARS-CoV-2 pandemic is limited. Using a longitudinal population-based study design, we assessed the association between SARS-CoV-2 infection and changes in body composition.

Methods:

Community-dwelling older adults living in a rural Ecuadorian village received body composition determinations before and 1 year after the pandemic as well as serological tests for detection of SARS-CoV-2 antibodies. The independent association between SARS-CoV-2 infection and abnormalities in body composition at follow-up was assessed by fitting linear mixed models for longitudinal data.

Results:

Of 327 enrolled individuals, 277 (85%) received baseline and follow-up body composition determinations, and 175 (63%) of them became SARS-CoV-2 seropositive. Overall, diet and physical activity deteriorated during the follow-up. Multivariate random-effects generalized least squares regression models that included the impact of time and seropositivity on follow-up body composition, showed that neither variable contributed to a worsening in body composition. Multivariate logistic regression models disclosed that the serological status at follow-up cannot be predicted by differences in body composition and other baseline covariates.

Conclusions:

Study results suggest no increased susceptibility to SARS-CoV-2 infection among older adults with abnormal body composition and no significant changes as a result of worse physical activity and dietary habits or seropositivity during the length of the study. Together with a previous study in the same population that showed decrease in hand-grip strength after SARS-CoV-2, results confirm that dynapenia (and not sarcopenia) is associated with SARS-CoV-2 infection in older adults.

A literature review of consent declines and consent withdrawals in randomized controlled trials conducted during the COVID-19 pandemic

Objectives:

We evaluated the extent of consent declines and consent withdrawals during the COVID-19 pandemic as seen in published randomized controlled trials (RCTs) and compared it with non-COVID-19 RCTs published at the same time and two historical controls.

Methods:

PubMed/Medline only was searched using key-word “COVID-19” and “RCTs” separately, and filtered for COVID-19 RCTs and non-COVID-19 RCTs respectively, published during a nine-month period (1 Feb - 1 Nov 2020). Exclusions were study protocols, observational studies, interim analysis of RCT data and RCTs with missing data. Primary outcome measures were the proportion of consent declines and consent withdrawals as percentage of total participants screened and randomized respectively in COVID-19 RCTs. We compared consent declines and consent withdrawals of COVID-19 RCTs with non-COVID-19 RCTs and two earlier studies on the same topic that served as historical controls (non-pandemic setting).

Results:

The search yielded a total of 111 COVID-19 RCTs and 49 non-COVID-19 RCTs. Of these, 39 (35.13%) COVID-19 RCTs and 11 (22.45%) non-COVID-19 RCTs were finally analysed. A total of 770/17759 (4.3%) consent declines and 100/7607 (1.31%) consent withdrawals were seen in 39 COVID-19 RCTs. A significant difference was observed in consent declines between COVID-19 vs non-COVID-19 RCTs [4.3% vs 11.9%, p < 0.0001] and between COVID-19 RCTs vs two historical controls [(4.3% vs 8.6%, p < 0.0001) and (4.3% vs 21.1%, p < 0.0001), respectively].

Conclusion:

RCTs conducted during the COVID-19 pandemic appear to have significantly lower consent declines relative to non-COVID-19 RCTs during pandemic and RCTs conducted in non-pandemic settings.

SARS-CoV-2 in Rural Latin America. A Population-based Study in Coastal Ecuador

Antibodies to SARS-CoV-2 were detected in 303/673 rural Ecuadorian adults (45%), 77% of whom had compatible clinical manifestations. Seropositivity was associated with the use of open latrines. Our findings support the fears of mass spread of SARS-CoV-2 in rural Latin America and cannot exclude a contributing role for fecal-oral transmission.

Participants Attrition in a Longitudinal Study: The Malaysian Cohort Study Experience

The attrition rate of longitudinal study participation remains a challenge. To date, the Malaysian Cohort (TMC) study follow-up rate was only 42.7%. This study objective is to identify the cause of attrition among TMC participants and the measures to curb it. A total of 19,343 TMC participants from Kuala Lumpur and Selangor that was due for follow-up were studied. The two most common attrition reasons are undergoing medical treatment at another government or private health center (7.0%) and loss of interest in participating in the TMC project (5.1%). Those who were inclined to drop out were mostly Chinese, aged 50 years and above, unemployed, and had comorbidities during the baseline recruitment. We have also contacted 2183 participants for the home recruitment follow-up, and about 10.9% agreed to join. Home recruitment slightly improved the overall follow-up rate from 42.7% to 43.5% during the three-month study period.

Previously diagnosed obstructive sleep apnea is not associated with increased risk of SARS-CoV-2 infection in community-dwelling older adults living in a highly endemic setting

OBJECTIVE

In view of the high prevalence of obstructive sleep apnea (OSA) and the increasing global pandemic of SARS-CoV-2 infection, it is likely that many patients with OSA get exposed to this virus. Besides theoretical assumptions, there is no evidence that OSA may favor SARS-CoV-2 acquisition or may lead to a more severe disease. Taking the opportunity of the Atahualpa Project cohort, we aimed to assess the relationship between previously diagnosed OSA and SARS-CoV-2 infection in older adults living in rural Ecuador.

PATIENTS AND METHODS

SARS-CoV-2 antibodies were determined in 180 individuals aged > 60 years that underwent polysomnography previously to this novel pandemic. Those with OSA remained untreated due to income limitations. Exposure-effect models were fitted with OSA as the exposure, SARS-CoV-2 seropositivity and symptomatology as the outcomes, and confounders - age, gender, obesity, arterial hypertension, diabetes mellitus, hypercholesterolemia, individuals per house, home confinement - as independent variables.

RESULTS

A total of 87 (48%) individuals were seropositive to SARS-CoV-2, 77% of whom were symptomatic. The mean apnea/hypopnea index was 11.1 ± 11.7 episodes per hour, with 83 (46%) individuals having mild, and 38 (21%) moderate-to-severe OSA. Exposure-effect models demonstrated lack of relationship between OSA and SARS-CoV-2 seropositivity and symptomatology.

CONCLUSIONS

This study shows no relationship between history of OSA and SARS-CoV-2 seropositivity or symptomatology, opposing previous suggestions that persons with OSA are more prone to acquire the infection and have a more severe disease.

Social Determinants of Health and Risk of SARS-CoV-2 Infection in Community-Dwelling Older Adults Living in a Rural Latin American Setting

High social risk, as measured by the social determinants of health (SDH), may increase the risk of SARS-CoV-2 infection. However, this association has not been studied in rural communities. Using the Atahualpa Project cohort, we aimed to assess the association between SDH and SARS-CoV-2 seropositivity in community-dwelling older adults living in rural Ecuador. SARS-CoV-2 antibodies were determined in 319 individuals aged ≥ 60 years that completed a validated field instrument to assess their social risk before the introduction of this novel pandemic. Multivariate models were fitted to assess the independent association between SDH-and each of their components-and SARS-CoV-2 seropositivity, after adjusting for relevant covariates. According to the Gijon scale, 102 (32%) individuals had a high social risk (≥ 10 points). A total of 141 (44%) individuals were seropositive to SARS-CoV-2. A fully-adjusted logistic regression model showed an independent) association between social risk and SARS-CoV-2 positivity (OR 1.15; 95% CI 1.04-1.27; p = 0.008). For every unit of the total SDH score, the odds of SARS-CoV-2 seropositivity increased 15% (95% CI 3.7-27%). In addition, multivariate models showed that the individual component of SDH more strongly associated with SARS-CoV-2 seropositivity was housing, which suggested that lack of basic home facilities may increase the risk of SARS-CoV-2 infection. Knowledge on the association between high social risk and SARS-CoV-2 infection is indispensable for the development of cost-effective preventive strategies for controlling modifiable factors that are in the path of SARS-CoV-2 infection among older adults living in underserved communities.

Sleep quality deterioration in middle-aged and older adults living in a rural Ecuadorian village severely struck by the SARS-CoV-2 pandemic. A population-based longitudinal prospective study

Study objectives

This study assessed changes in sleep quality before and after the peak of the SARS-CoV-2 pandemic in community-dwellers enrolled in the Atahualpa Project.

Methods

Atahualpa residents aged ≥40 were eligible if they had a Pittsburgh Sleep Quality Index (PSQI) nine months before the pandemic and a lateral flow-based test for identification of SARS-CoV-2 antibodies during the peak of the pandemic. Six months later, individuals completed a follow-up PSQI. The independent relationship between SARS-CoV-2 infection and deterioration in sleep quality was assessed by fitting logistic mixed models for longitudinal data.

Results

Of 639 participants (mean age at baseline: 59±12.8 years), 325 (51%) had SARS-CoV-2 antibodies. A total of 185 (29%) individuals at baseline and 311 (49%) at follow-up were poor sleepers (p<0.001). Mixed logistic regression models demonstrated a significant increase in poor sleepers at follow-up (OR: 2.85; 95% C.I.: 2.16 – 3.75), which was more marked among SARS-CoV-2 seropositive subjects (OR: 3.8; 95% C.I.: 2.48 – 5.81). The adjusted proportion of poor sleepers increased from 29% to 56.2% (95% C.I.: 50.9 – 61.6%) among SARS-CoV-2 seropositive individuals, but only to 40.7% (95% C.I.: 35.3 – 46.1%) in their seronegative counterparts (p<0.001). Likewise, progression from a good to a poor sleeper status was higher among seropositive individuals than in their seronegative counterparts (38.1% versus 22.3%; p<0.001), after adjusting for relevant covariates.

Conclusions

This study shows a deleterious effect of SARS-CoV-2 in sleep quality. An effect of SARS-CoV-2 in disrupting sleep-related pathways cannot be ruled out.

Cognitive decline among individuals with history of mild symptomatic SARS-CoV-2 infection: A longitudinal prospective study nested to a population cohort

BACKGROUND AND PURPOSE

Neurological complications of SARS-CoV-2 infection are noticed among critically ill patients soon after disease onset. Information on delayed neurological sequelae of SARS-CoV-2 infection is nil. Following a longitudinal study design, the occurrence of cognitive decline among individuals with a history of mild symptomatic SARS-CoV-2 infection was assessed.

METHODS

Stroke- and seizure-free Atahualpa residents aged ≥40 years, who had pre-pandemic cognitive assessments as well as normal brain magnetic resonance imaging and electroencephalogram recordings, underwent repeated evaluations 6 months after a SARS-CoV-2 outbreak infection in Atahualpa. Patients requiring oxygen therapy, hospitalization, and those who had initial neurological manifestations were excluded. Cognitive decline was defined as a reduction in the Montreal Cognitive Assessment (MoCA) score between the post-pandemic and pre-pandemic assessments that was ≥4 points greater than the reduction observed between two pre-pandemic MoCAs. The relationship between SARS-CoV-2 infection and cognitive decline was assessed by fitting logistic mixed models for longitudinal data as well as exposure-effect models.

RESULTS

Of 93 included individuals (mean age 62.6 ± 11 years), 52 (56%) had a history of mild symptomatic SARS-CoV-2 infection. Post-pandemic MoCA decay was worse in seropositive individuals. Cognitive decline was recognized in 11/52 (21%) seropositive and 1/41 (2%) seronegative individuals. In multivariate analyses, the odds for developing cognitive decline were 18.1 times higher among SARS-CoV-2 seropositive individuals (95% confidence interval 1.75-188; p = 0.015). Exposure-effect models confirmed this association (β = 0.24; 95% confidence interval 0.07-0.41; p = 0.006).

CONCLUSIONS

This study provides evidence of cognitive decline among individuals with mild symptomatic SARS-CoV-2 infection. The pathogenesis of this complication remains unknown.

The association between aortic arterial stiffness, carotid intima-media thickness and carotid plaques in community-dwelling older adults: A population-based study

OBJECTIVE

Information on the associations among arterial stiffness, carotid intima-media thickness (cIMT) and carotid plaques as biomarkers of atherosclerosis is limited in diverse populations. We aimed to assess whether aortic pulse wave velocity (aPWV) - as a surrogate of arterial stiffness - is associated with increased cIMT and the presence of carotid plaques in a cohort of older adults of Amerindian ancestry.

METHODS

Atahualpa residents aged ≥60 years (n = 320) underwent aPWV determinations, and carotid ultrasounds for cIMT and plaque assessment. Multivariate models were fitted to assess the independent association between the aPWV, and cIMT and carotid plaques, after adjusting for relevant confounders. Differences in risk factors across these biomarkers were investigated.

RESULTS

Mean values of aPWV were 10.3 ± 1.8 m/s, and those of cIMT were 0.91 ± 0.21 mm (24% had a cIMT >1 mm). Carotid plaques were observed in 118 (37%) subjects. In univariate analyses, risk factors associated with an increased aPWV included age, female gender, poor physical activity and high blood pressure. An increased cIMT was associated with age, male gender, a poor diet, high blood pressure and severe tooth loss. The presence of carotid plaques was associated with increasing age, poor physical activity and high blood pressure. Multivariate models showed a significant association between aPWV and cIMT (β: 0.028; 95% C.I.: 0.001-0.056; p = 0.047) but not between aPWV and carotid plaques (OR: 1.14; 95% C.I.: 0.83-1.56; p = 0.423).

CONCLUSIONS

This study shows an independent association between aPWV and cIMT but not with carotid plaques. These biomarkers may indicate distinct phenotypes for atherosclerosis.

Cerebrovascular Correlates of Dementia in Community-Dwelling Older Adults Living in Rural Communities - The Three Villages Study. Rationale and Protocol of a Population-Based Prospective Cohort Study

BACKGROUND

Despite the assumption that dementia is increasing in rural areas of Latin America, there is no information on the burden and risk factors leading to dementia in these settings.

AIMS

To assess prevalence and incidence of dementia, and its cerebrovascular correlates in an established cohort of community-dwelling older adults living in rural Ecuador, and to explore the impact of dementia on functional disability and the role of the social determinants of health in the above-mentioned relationships.

DESIGN

Population-based, cohort study with cross-sectional and longitudinal components. Baseline clinical interviews will focus on the assessment of cognitive performance and dementia by means of the clinical dementia rating scale (CDRS). Functional disability and social determinants of health will be correlated with CDRS scores. In addition, participants will undergo interviews and procedures to assess cardiovascular risk factors and signatures of brain damage, cerebral small vessel disease, and other stroke subtypes. The CDRS and the Functional Activities Questionnaire will be administered every year to assess the rate of incident dementia and the severity of functional disability. Neuroimaging studies will be repeated at the end of the study (5 years) to assess the impact of newly appeared cerebral and vascular lesions on cognitive decline.

COMMENT

This study will allow determine whether cerebrovascular diseases are in the path of dementia development in these rural settings. This may prove cost-effective for the development of preventive strategies aimed to control modifiable factors and reduce disability in patients with dementia living in underserved populations.

Cognitive decline is not influenced by the marital status or living arrangements in community-dwelling adults living in a rural setting. A population-based prospective cohort study

Little is known on factors influencing cognitive decline in rural communities. Using the Atahualpa Project cohort, we aimed to assess whether the marital status or living arrangements influenced cognitive decline in community-dwelling adults living in an Ecuadorian rural village. The study included 629 Atahualpa residents aged ≥40 years who had a follow-up Montreal Cognitive Assessment (MoCA) repeated at least one year after baseline. Multivariate longitudinal linear models were fitted to assess differences between the marital status and living arrangements and cognitive decline (as the outcome). A total of 411 participants were married. The remaining 218 were either single, divorced or widowed (191 of them lived with family members and the others lived alone). Enrolled individuals contributed 2088.4 person-years of follow-up (mean: 3.3 ± 1.1 years). The mean baseline MoCA was 22.1 ± 4.5 points and the follow-up MoCA was 20.6 ± 4.8 points (p = 0.001). Overall, 394 (63%) individuals had lower MoCA scores at follow-up. A fully-adjusted longitudinal linear model showed no differences in MoCA decline across married and non-married individuals (β: -0.15; 95% C.I.: -0.55 - 0.26; p = 0.477). When the subset of non-married individuals was taken into account for analyses, multivariate longitudinal linear models showed no differences in the severity of cognitive decline across individuals living alone versus those living with family members (β: 0.28; 95% C.I.: -0.68 - 1.24; p = 0.572). In this study, the marital status or living arrangements had no influence on cognitive decline in the follow-up.

Cardiovascular Health Status Among Community-Dwelling Ecuadorian Natives Living in Neighboring Rural Communities: The Three Villages Study

Knowledge of cardiovascular health (CVH) status in rural communities is essential to implement cost-effective strategies aimed to address the growing burden of cardiovascular diseases in these settings. Here, we report on the CVH status and health metrics of 1508 community-dwellers aged ≥ 40 years in three neighboring rural villages of Coastal Ecuador (Atahualpa, El Tambo, and Prosperidad). According to the American Heart Association, a poor CVH status is designated when at least one cardiovascular health metric is in the poor range. About 70% of individuals in the villages studied had a poor CVH status, with no overall differences across villages. However, the relative prevalence of poor health metrics varied. Using Atahualpa as the referent village, a multinomial logistic regression model showed that El Tambo residents were more often smokers and had a worse diet, while Prosperidad residents had more high blood pressure but better fasting glucose levels. Probabilities of having poor health metrics were lower in Atahualpa than in El Tambo (p < 0.001), but not better than in Prosperidad (p = 0.097). Predictive estimates of having poor health metrics were significantly higher in El Tambo than in Atahualpa or in Prosperidad. This comparative study demonstrates that the CVH status of rural populations of coastal Ecuador is basically similar. However, individual health metrics in the poor range were found to vary across villages. While the three villages are generally comparable, interventions should be tailored according to local priorities. The same may occur in other rural communities, but more studies are needed to confirm our findings.

Effect of Heart Rate Variability on the Association Between the Apnea-Hypopnea Index and Cerebral Small Vessel Disease

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.