J Epidemiol 2014;24(4):281-286 doi:10.2188/jea.JE20130114
Original Article
Self-reported Snoring and Carotid Atherosclerosis in Middle-aged and Older Adults: The Korean Multi-Rural Communities Cohort Study Young-Hoon Lee1,2, Sun-Seog Kweon3,4, Bo Youl Choi5, Mi Kyung Kim5, Byung-Yeol Chun6, Dong Hoon Shin7, and Min-Ho Shin3 1
Department of Preventive Medicine & Institute of Wonkwang Medical Science, Wonkwang University School of Medicine, Iksan, Jeonbuk, South Korea 2 Regional Cardiocerebrovascular Center, Wonkwang University Hospital, Iksan, Jeonbuk, South Korea 3 Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, South Korea 4 Jeonnam Regional Cancer Center, Chonnam National University Hwasun Hospital, Hwasun, South Korea 5 Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea 6 Department of Preventive Medicine, School of Medicine, and Health Promotion Research Center, Kyungpook National University, Daegu, South Korea 7 Department of Preventive Medicine, Keimyung University School of Medicine, Daegu, South Korea Received August 19, 2013; accepted February 17, 2014; released online April 12, 2014 Copyright © 2014 Young-Hoon Lee et al. This is an open access article distributed under the terms of Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
ABSTRACT Background: We investigated the relation of self-reported snoring with carotid intima-media thickness (IMT) and plaque in community-dwelling middle-aged and older adults. Methods: In total, 7330 community-dwelling subjects in the Korean Multi-Rural Communities Cohort Study were included in the analysis. Common carotid artery IMT (CCA-IMT) and plaque were evaluated by high-resolution B-mode ultrasonography. Snoring status was evaluated using a structured interview. Results: Snorers had a significantly greater average CCA-IMT than non-snorers (0.726 vs 0.713 mm; P < 0.001), after adjusting for age and gender. The odds ratios (OR) for high CCA-IMT (fifth quintile) were significantly higher for snorers than for non-snorers in multivariate-adjusted analysis (OR 1.25, 95% confidence interval [CI] 1.10–1.42). However, there was no significant relationship between snoring and carotid plaques. Conclusions: Our data suggest that self-reported snoring is significantly associated with increased IMT, but not with the presence of plaques. These findings suggest that early screening and intervention for snoring in the general population are needed to prevent adverse cardiovascular events. Key words: snoring; atherosclerosis; carotid intima-media thickness; carotid artery plaque
as the link between snoring and cardiovascular disease (CVD). Alternatively, a non-metabolic pathway that mediates the relationship between snoring and CVD, such as carotid atherosclerosis, has been proposed.16,17 Increased carotid intima-media thickness (IMT) and atherosclerotic plaques are surrogate markers of subclinical atherosclerosis and strong predictors of CVD, such as stroke and myocardial infarction.18,19 Few epidemiologic studies have examined the association between snoring and carotid atherosclerosis; however, those that did reported inconsistent associations.20,21 To date, whether or not self-reported snoring is significantly associated with carotid atherosclerosis in the general population remains undetermined. The aim of this study was
INTRODUCTION Snoring is a sound emitted from the upper airway of the throat during sleep and is an indicator of increased resistance through the airway.1 Previous studies have reported that male gender, age, obesity, alcohol consumption, cigarette smoking, menopause, physical inactivity, and family history were risk factors for snoring.2–9 Epidemiologic evidence has also shown that self-reported snoring was associated with increased incidence of cardiovascular events.10–13 Since previous epidemiologic studies have suggested that snoring is significantly associated with metabolic syndrome,14,15 metabolic components have been considered
Address for correspondence. Min-Ho Shin, MD, PhD, Department of Preventive Medicine, Chonnam National University Medical School, 5 hak-1-dong, Dong-gu, 501-746 Gwangju City, South Korea (e-mail: [email protected]).
281
282
Snoring and Carotid Atherosclerosis
to investigate the association between self-reported snoring and carotid atherosclerosis in community-dwelling middleaged and elderly Korean men and women.
METHODS Study population The Korean Multi-Rural Communities Cohort Study, which is part of the Korean Genome Epidemiology Study, was initiated in 2004 with the aim of constructing a genomic cohort and investigating the risk factors for CVD in rural communities. As the baseline, 9696 subjects, aged ≥40 years, were recruited between January 2005 and February 2010 from three centers: Yangpyeong in Gyeonggi-do (n = 3183), Namwon in Jeollabuk-do (n = 3408), and Goryeong in Gyeongsangbukdo (n = 3105). The majority of the subjects were farmers and housewives. We excluded subjects who had a previous history of coronary heart disease or cerebrovascular disease during the baseline survey, those who did not provide information on their snoring, and those who did not undergo carotid ultrasonography. In total, 7330 subjects (2901 men and 4429 women) aged 40–91 years were included in the final analysis. This study was conducted in accordance with the Declaration of Helsinki guidelines, and all procedures involving human subjects were approved by the Institutional Review Boards of Hanyang University, Chonnam National University, and Keimyung University. All subjects were fully informed of the study content and gave written informed consent for the use of their data. Interview and examination We administered a questionnaire and an examination using a standardized protocol to overcome the limitations of multicenter studies. All interviewers and examiners were trained by the same personnel at the coordinating center. Information on demographics, smoking, alcohol intake, exercise, medical history, and medications was collected, using a questionnaire administered by well-trained interviewers. Height was measured to the nearest 0.1 cm using a standard height scale, and weight in light clothing without shoes was measured to the nearest 0.1 kg using a metric weight scale. Body mass index (BMI) was calculated as weight (kg) divided by height (m) squared. Waist circumference was measured to the nearest 0.1 cm at the midpoint between the lowest rib margin and the iliac crest during expiration. Blood pressure was measured from the right upper arm, using a standard mercury sphygmomanometer (Baumanometer; WA Baum Co., Inc., Copiague, NY, USA) and a standard cuff. Two consecutive blood-pressure measurements were performed after each subject had been sitting for at least 5 min. The subjects were instructed to relax as much as possible, and not to talk during the measurement procedure. The first appearance (phase I) and disappearance (phase V) of Korotkoff sounds were used to define systolic
J Epidemiol 2014;24(4):281-286
blood pressure and diastolic blood pressure, respectively. Systolic and diastolic blood pressures were recorded to the nearest 2 mm Hg. If two systolic or diastolic blood pressures were more than 5 mm Hg apart, an additional measurement was performed, and the mean value of the closest two measurements was used for the subsequent analyses. Blood samples taken from the antecubital vein were collected from each subject during the morning after an 8-h overnight fast, and all biochemical markers were evaluated on the same day. Total serum cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, and fasting blood glucose levels were analyzed using an ADVIA1650 Automatic Analyzer (Siemens, New York, NY, USA). Information on snoring Snoring status was evaluated using a structured interview, including two questions: (1) do you know, or have you ever heard that you snore? (yes or no); and (2) how often do you snore? (
Original Article
Self-reported Snoring and Carotid Atherosclerosis in Middle-aged and Older Adults: The Korean Multi-Rural Communities Cohort Study Young-Hoon Lee1,2, Sun-Seog Kweon3,4, Bo Youl Choi5, Mi Kyung Kim5, Byung-Yeol Chun6, Dong Hoon Shin7, and Min-Ho Shin3 1
Department of Preventive Medicine & Institute of Wonkwang Medical Science, Wonkwang University School of Medicine, Iksan, Jeonbuk, South Korea 2 Regional Cardiocerebrovascular Center, Wonkwang University Hospital, Iksan, Jeonbuk, South Korea 3 Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, South Korea 4 Jeonnam Regional Cancer Center, Chonnam National University Hwasun Hospital, Hwasun, South Korea 5 Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea 6 Department of Preventive Medicine, School of Medicine, and Health Promotion Research Center, Kyungpook National University, Daegu, South Korea 7 Department of Preventive Medicine, Keimyung University School of Medicine, Daegu, South Korea Received August 19, 2013; accepted February 17, 2014; released online April 12, 2014 Copyright © 2014 Young-Hoon Lee et al. This is an open access article distributed under the terms of Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
ABSTRACT Background: We investigated the relation of self-reported snoring with carotid intima-media thickness (IMT) and plaque in community-dwelling middle-aged and older adults. Methods: In total, 7330 community-dwelling subjects in the Korean Multi-Rural Communities Cohort Study were included in the analysis. Common carotid artery IMT (CCA-IMT) and plaque were evaluated by high-resolution B-mode ultrasonography. Snoring status was evaluated using a structured interview. Results: Snorers had a significantly greater average CCA-IMT than non-snorers (0.726 vs 0.713 mm; P < 0.001), after adjusting for age and gender. The odds ratios (OR) for high CCA-IMT (fifth quintile) were significantly higher for snorers than for non-snorers in multivariate-adjusted analysis (OR 1.25, 95% confidence interval [CI] 1.10–1.42). However, there was no significant relationship between snoring and carotid plaques. Conclusions: Our data suggest that self-reported snoring is significantly associated with increased IMT, but not with the presence of plaques. These findings suggest that early screening and intervention for snoring in the general population are needed to prevent adverse cardiovascular events. Key words: snoring; atherosclerosis; carotid intima-media thickness; carotid artery plaque
as the link between snoring and cardiovascular disease (CVD). Alternatively, a non-metabolic pathway that mediates the relationship between snoring and CVD, such as carotid atherosclerosis, has been proposed.16,17 Increased carotid intima-media thickness (IMT) and atherosclerotic plaques are surrogate markers of subclinical atherosclerosis and strong predictors of CVD, such as stroke and myocardial infarction.18,19 Few epidemiologic studies have examined the association between snoring and carotid atherosclerosis; however, those that did reported inconsistent associations.20,21 To date, whether or not self-reported snoring is significantly associated with carotid atherosclerosis in the general population remains undetermined. The aim of this study was
INTRODUCTION Snoring is a sound emitted from the upper airway of the throat during sleep and is an indicator of increased resistance through the airway.1 Previous studies have reported that male gender, age, obesity, alcohol consumption, cigarette smoking, menopause, physical inactivity, and family history were risk factors for snoring.2–9 Epidemiologic evidence has also shown that self-reported snoring was associated with increased incidence of cardiovascular events.10–13 Since previous epidemiologic studies have suggested that snoring is significantly associated with metabolic syndrome,14,15 metabolic components have been considered
Address for correspondence. Min-Ho Shin, MD, PhD, Department of Preventive Medicine, Chonnam National University Medical School, 5 hak-1-dong, Dong-gu, 501-746 Gwangju City, South Korea (e-mail: [email protected]).
281
282
Snoring and Carotid Atherosclerosis
to investigate the association between self-reported snoring and carotid atherosclerosis in community-dwelling middleaged and elderly Korean men and women.
METHODS Study population The Korean Multi-Rural Communities Cohort Study, which is part of the Korean Genome Epidemiology Study, was initiated in 2004 with the aim of constructing a genomic cohort and investigating the risk factors for CVD in rural communities. As the baseline, 9696 subjects, aged ≥40 years, were recruited between January 2005 and February 2010 from three centers: Yangpyeong in Gyeonggi-do (n = 3183), Namwon in Jeollabuk-do (n = 3408), and Goryeong in Gyeongsangbukdo (n = 3105). The majority of the subjects were farmers and housewives. We excluded subjects who had a previous history of coronary heart disease or cerebrovascular disease during the baseline survey, those who did not provide information on their snoring, and those who did not undergo carotid ultrasonography. In total, 7330 subjects (2901 men and 4429 women) aged 40–91 years were included in the final analysis. This study was conducted in accordance with the Declaration of Helsinki guidelines, and all procedures involving human subjects were approved by the Institutional Review Boards of Hanyang University, Chonnam National University, and Keimyung University. All subjects were fully informed of the study content and gave written informed consent for the use of their data. Interview and examination We administered a questionnaire and an examination using a standardized protocol to overcome the limitations of multicenter studies. All interviewers and examiners were trained by the same personnel at the coordinating center. Information on demographics, smoking, alcohol intake, exercise, medical history, and medications was collected, using a questionnaire administered by well-trained interviewers. Height was measured to the nearest 0.1 cm using a standard height scale, and weight in light clothing without shoes was measured to the nearest 0.1 kg using a metric weight scale. Body mass index (BMI) was calculated as weight (kg) divided by height (m) squared. Waist circumference was measured to the nearest 0.1 cm at the midpoint between the lowest rib margin and the iliac crest during expiration. Blood pressure was measured from the right upper arm, using a standard mercury sphygmomanometer (Baumanometer; WA Baum Co., Inc., Copiague, NY, USA) and a standard cuff. Two consecutive blood-pressure measurements were performed after each subject had been sitting for at least 5 min. The subjects were instructed to relax as much as possible, and not to talk during the measurement procedure. The first appearance (phase I) and disappearance (phase V) of Korotkoff sounds were used to define systolic
J Epidemiol 2014;24(4):281-286
blood pressure and diastolic blood pressure, respectively. Systolic and diastolic blood pressures were recorded to the nearest 2 mm Hg. If two systolic or diastolic blood pressures were more than 5 mm Hg apart, an additional measurement was performed, and the mean value of the closest two measurements was used for the subsequent analyses. Blood samples taken from the antecubital vein were collected from each subject during the morning after an 8-h overnight fast, and all biochemical markers were evaluated on the same day. Total serum cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, and fasting blood glucose levels were analyzed using an ADVIA1650 Automatic Analyzer (Siemens, New York, NY, USA). Information on snoring Snoring status was evaluated using a structured interview, including two questions: (1) do you know, or have you ever heard that you snore? (yes or no); and (2) how often do you snore? (
