Dyslipidemia is a major risk factor contributing to cardiovascular disease and its prevalence is steadily rising. Although screening tests are readily accessible, dyslipidemia remains undertreated. Evaluating health behavior patterns after diagnosis may help improve lifestyle interventions for the management of dyslipidemia.
Data from the fifth Korean National Health and Nutrition Examination Survey 2010–2012 were used. A total of 6,624 dyslipidemia patients over 20 years old were included according to National Cholesterol Education Program-Adult Treatment Panel III guidelines. Logistic regression analysis was completed using a weighted method to determine whether awareness of dyslipidemia was associated with health behavior. Health behavior was divided into two categories: behavioral factors (smoking, alcohol consumption, exercise) and nutritional factors (adequate intake of fiber, carbohydrate, fat, protein).
There were no significant differences in health behavior among dyslipidemia patients according to awareness after adjustment for covariates, diabetes and hypertension. Awareness in women was associated with decreased smoking (odds ratio [OR], 0.55; 95% confidence interval [CI], 0.32 to 0.94), but when adjusted for diabetes and hypertension the result was not significant (OR, 0.61; 95% CI, 0.35 to 1.06). The same pattern applied to intake of carbohydrate in men (OR, 1.28; 95% CI, 0.99 to 1.67) and protein in women (OR, 1.22; 95% CI, 0.98 to 1.50). In subgroup analysis, awareness of dyslipidemia in men without hypertension or diabetes was associated with adequate intake of carbohydrate (OR, 1.70; 95% CI, 1.06 to 2.72).
Increasing awareness alone may not be enough to improve healthy behavior in patients with dyslipidemia. Efforts including patient education and counseling through a multi-team approach may be required.
Cardiovascular disease (CVD) is one of the main causes of morbidity and mortality worldwide.
Meanwhile, the prevalence of dyslipidemia is steadily rising in Korea, and statistics published by the Korean Society of Lipidology and Atherosclerosis (KSLA) revealed that in 2013 57.6% of men and 38.3% of women, accounting for a total of 47.8% of people over 30 years of age (more than 16 million), had dyslipidemia. When the low-density lipoprotein cholesterol (LDLC) cutoff value was set to 100 mg/dL for diabetic patients, 9 out of every 10 diabetic adults had dyslipidemia. For patients with hypertension, 2 out of every 3 hypertensive adults were diagnosed with dyslipidemia.
The use of lipid-lowering medications such as statin and fibrate are important for the treatment of dyslipidemia, especially in high-risk patients. However, lifestyle interventions are also important for managing dyslipidemia and are considered initially after diagnosis, since dietary factors can influence lipid levels and regular exercise improves lipid profiles, while smoking has been known to have a detrimental effect.
Previous reports have studied the prevalence, awareness, and treatment of dyslipidemia in Korea. Although awareness and treatment rates are slowly rising, their rates are still low (13.7% and 7.4% in 2010 compared to 6.1% and 1.9% in 2005, respectively).
Lack of awareness about dyslipidemia may act as an additional barrier to adequate health behavior. However, whether awareness of dyslipidemia affects health behavior is not clear. In a study by Kitagawa et al., patients with high awareness of their health status showed a positive attitude towards diet and exercise as lipid-lowering treatment, and high adherence to drug therapy. However, subjects were limited to high-risk patients on prescription for pravastatin making it difficult to apply the results to the general population.
No other studies analyzing awareness of dyslipidemia and associated factors were found by the authors. Therefore, this study compared adherence to health behavior according to clinical guidelines between dyslipidemia subjects who were aware of their diagnosis and those who were not, with higher adherence expected in the awareness group.
This study was performed using data from the fifth Korean National Health and Nutrition Survey 2010–2012 (KNHANES V). The KNHANES is a nationally representative study conducted regularly by the Korea Centers for Disease Control and Prevention to assess the health and nutritional status of non-institutionalized civilians in Korea. It uses a multi-stage probability sample design and trained interviewers to administer questionnaires to participants. The KNHANES V is based on data from 3,800 households in 576 randomly selected survey areas, with the number selected in proportion to the size of each area.
Blood samples were collected from each participant the morning after fasting for at least 8 hours. Samples were processed, refrigerated immediately, and transported to the central laboratory to be analyzed within 24 hours after transportation. Total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), triglycerides (TG), and fasting glucose levels were assessed using a Hitachi 7600 automatic chemistry analyzer (Hitachi, Tokyo, Japan). Direct LDLC measurements that were assessed by the automatic analyzer were used when available (participants eligible for sampling of heavy metal levels or with TG levels ≥200 mg/dL), and when unavailable, the Friedwald formula was used if the TG level was less than 400 mg/dL. Blood pressure was measured using a mercury sphygmomanometer (Baumanometer; WA Baum Co. Inc., Copiague, NY, USA) 3 times consecutively on the right arm with the participant in a seated position after at least 5 minutes of rest. The final blood pressure was obtained by averaging the second and third blood pressure measurements.
Dyslipidemia was defined by levels of TC (≥240 mg/dL), HDLC (<40 mg/dL), TG (≥200 mg/dL), and LDLC (≥160 mg/dL, ≥130 mg/dL, or ≥100 mg/dL according to risk category) based on the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) guidelines,
Dyslipidemia awareness was assessed by the questions, “Have you been diagnosed with dyslipidemia by a doctor?" and “Are you currently suffering from dyslipidemia?" Patients who answered “yes" to either question were considered to be aware of their condition and assigned to the awareness group. Those who were diagnosed with dyslipidemia according to assessment of their lipid levels according to the NCEP-ATP III guidelines, but answered “no" to the aforementioned questions were included in the control group (unawareness group). Controlled dyslipidemia was also defined according to target levels set by NCEP-ATP III guidelines according to risk category.
Diabetes mellitus was identified based on fasting blood glucose levels (≥126 mg/dL) or use of insulin or oral hypoglycemic agents.
The study population was divided into two groups according to the definition of obesity (BMI ≥25 kg/m2) by the World Health Organization Regional Office for the Western Pacific Region and adopted by the Korean Society for the Study of Obesity.
Information related to health behavior that has been reported as being beneficial for the control of lipid levels was collected from the KNHANES V database, and these were divided into two groups: behavioral risk factors, and nutritional risk factors. KSLA 2015 and International Atherosclerosis Society (IAS) 2013 guidelines were used when applicable.
Information on current smoking status was collected through a self-reporting questionnaire, and those who answered that they smoked, or occasionally smoked, were considered current smokers, regardless of the amount. Smoking is a major cause of atherosclerotic cardiovascular disease (ASCVD), and the IAS states that high priority must be given to the prevention or cessation of smoking in lifestyle intervention for dyslipidemia.
Data on excessive alcohol consumption (≥3 standard drinks per occasion) were also collected through the self-reporting questionnaire. KSLA 2015 guidelines recommend limiting alcohol intake to 1–2 drinks per occasion.
Adequate physical activity was also assessed through answers to questionnaires and participants were considered to engage in adequate physical activity if they reported having carried out over 30 minutes of moderate intensity physical activity at least 5 days per week, or over 20 minutes of heavy intensity at least 3 per week. Epidemiological studies have shown that physical inactivity is associated with increased risk for ASCVD and regular physical activity has beneficial effects on lipoproteins.
Nutritional factors were measured based on adherence to dietary recommendations that could be assessed using nutritional information provided by the KNHANES V. Therefore, adequate intake of macronutrients that was monitored by performing a 24-hour food recall and analyzed by the CAN-Pro software ver. 3.0 (Korean Nutrition Society, Seoul, Korea) was compared between the awareness groups. Adequate fiber intake (≥25 g/d), carbohydrate intake (<65% of total calories per day), fat intake (<30% of total calories per day), and protein intake (≥15% of total calories per day) were analyzed. The 2015 KSLA guidelines recommend limiting total daily carbohydrate intake and total fat intake to less than 30% of total calories per day and eating food rich in fiber for an intake of over 25 g of fiber per day.
All statistical analyses were performed using STATA statistical software ver. 14.0 (Stata Corp., College Station, TX, USA). All analyses were weighted to the Korean standard population from the years 2010 to 2012, reflecting the sampling method, response rate, and population structure of the KNHANES study.
Unpaired t-tests and chi-square tests were applied to continuous variables and categorical variables respectively in order to compare mean values and percentages of demographic and clinical characteristics between dyslipidemia patients according to awareness. Logistic regression was used to analyze which variables of health behavior were associated with awareness of dyslipidemia after adjusting for age. Afterwards, multivariable logistic regression was performed for each health behavior adjusting for age, education level, residential area (rural or urban), household income, self-perceived health status, marital status, and obesity (BMI ≥25 kg/m2). Adjusted OR, 95% confidence intervals (CI), and P-values were measured for the display of strength of each association. A P-value of <0.05 was considered significant.
The characteristics of the study population are described in
The mean age of the group who were aware of their condition was higher than that of the group that was unaware in both men and women. With respect to self-perceived health status, 14.3% of male patients in the unaware group responded that their health status was poor or very poor while 26.2% of those in the aware group gave the same response. Among men, 13.4% of the unaware and 17.5% of the aware received an elementary school or lower level of education, while 41.1% of women unaware of their dyslipidemia status received an elementary school or lower level of education and 52.2% of aware women reported receiving the same degree of education.
Awareness of dyslipidemia in both male and female patients was associated with a higher prevalence of diabetes mellitus and hypertension. Lipid profiles were also significantly favorable in aware groups with higher HDLC levels and lower TC, TG, and LDLC levels in both male and female dyslipidemia patients, although differences in the level of TG was not statistically significant in men.
Both men and women who were aware of their diagnosis of dyslipidemia had lower current smoking percentages (38.5% and 3.6%, respectively), and fewer aware women were likely to consume alcohol in excess (23.8% vs. 13.5%). When adjusted for other characteristics, female patients in the awareness group had a lower current smoking rate compared with those in the unaware group (OR, 0.55; 95% CI, 0.32 to 0.94), but when adjusted for the prevalence of diabetes and hypertension, the result was not statistically significant (OR, 0.61; 95% CI, 0.35 to 1.06). As can be observed in
The only favorable nutritional factor observed in the aware groups by crude proportions was adequate intake of fat found in women aware of their diagnosis of dyslipidemia (93.7% vs. 96.0%). Although female patients aware of their diagnosis showed a higher OR for adequate protein intake (OR, 1.26; 95% CI, 1.00 to 1.58) when adjusted for covariates, the result was not statistically significant when additionally adjusted for the prevalence of diabetes and hypertension (OR, 1.22; 95% CI, 0.98 to 1.53). Men also showed a higher OR for adequate intake of carbohydrate (OR, 1.33; 95% CI, 1.04 to 1.72), but when adjusted for diabetes and hypertension the result was not significant (OR, 1.28; 95% CI, 0.99 to 1.67). There were no other statistically significant differences as shown in
In subgroup analysis of dyslipidemia patients without either hypertension or diabetes, men aware of their diagnosis of dyslipidemia had a higher OR for adequate carbohydrate intake (OR, 1.70; 95% CI, 1.06 to 2.72) after adjusting for other factors (
In the subgroup analysis of dyslipidemia subjects with diabetes mellitus, there were no significant differences in health behavior according to awareness (
This study suggests that there is minimal difference in health behavior between those aware and those unaware of their diagnosis of dyslipidemia among Korean adults over the age of 20 years. There was no statistically significant difference in health behavior and adequate macronutrient intake between the awareness groups after adjusting for demographic variables and the prevalence of diabetes and hypertension, perhaps because diabetes and hypertension are more important factors influencing adherence to health behavior. The only beneficial health behavior was found in the subgroup analysis, where adequate carbohydrate intake was observed in men with neither hypertension nor diabetes.
When analyzing crude proportions of adequate health behavior, rates of current smoking (38.5%) and excessive alcohol consumption (66.1%) in men aware of their diagnosis of dyslipidemia were higher than desirable and rates of adequate physical activity in both male and female dyslipidemia patients (19.8% in aware men and 15.9% in aware women) showed rates with ample room for improvement. Although rates of adequate fat intake were high in patients with dyslipidemia (93.4% in aware men and 96.0% in aware women), adequate intake of fiber in all subjects (2.7% in aware men and 1.2% in aware women), and carbohydrate in women (18.5% in aware women) were comparatively low. These results show that there is room for improvement in health behavior in the general population with dyslipidemia, even in those aware of their conditions. Unfortunately, awareness was not significantly associated with the health behaviors mentioned above after adjustment for covariates, implying that merely increasing awareness is not enough to promote health behavior. However, causality cannot be determined due to the cross-sectional design of this study.
Adequate control of lipid levels is important. A 1% reduction in total serum cholesterol levels can lead to a 2% to 3% reduction in risk of coronary disease,
Results published by the Korean Ministry of Health and Welfare on data from the KNHANES reveal that awareness rates of dyslipidemia are steadily rising (24.0% in 2005 to 59.0% in 2013); however, it is still low when compared to published results of awareness of other chronic diseases such as hypertension (65.3% in 2013) and diabetes (74.3% in 2013).
Although additional long-term studies are required to evaluate whether awareness of dyslipidemia can affect health behavior, results of this study suggest that awareness of dyslipidemia alone may not be enough to promote health behavior. One explanation can be that patients may be lacking in proper dyslipidemia education and instruction from their healthcare providers. This may also be the case for other chronic diseases. A study carried out on KNHANES 1998–2012 data analyzing adherence to dietary recommendations among Korean adults with diabetes mellitus concluded that Korean patients with diabetes have poor adherence to dietary recommendations and healthy lifestyle published by the Korean Diabetes Association regardless of awareness of diabetes.
The development and establishment of public health policies to promote adequate behavior for the management of dyslipidemia may also be of help. A project carried out in Finland found that health promotion campaigns at a national level through various activities (such as media campaigns and health fares) can help increase population awareness on prevention of chronic diseases and prompt subjects to make beneficial lifestyle changes.
In addition, interventions at community levels may also be helpful. Fritsch et al.
This study has several strengths. First, to the knowledge of the authors, this is the first study to analyze adherence to health behavior recommended by clinical guidelines for the management of dyslipidemia according to patients' awareness. Furthermore, this study was conducted using data from a nationally representative sample of the Korean population, making the estimates of this study generalizable to the population of dyslipidemia patients in Korea. Additionally, KNHANES provides data collected through standardized laboratory and physical measurements. Finally, data was used from three consecutive years, providing a large sample size and powering the statistical ability to report associations.
This study also has several limitations. Because it is based on a cross-sectional design, it is difficult to assess any temporal relationship between awareness of dyslipidemia and health behavior and adequate macronutrient intake. Although daily intake of macronutrients was assessed for nutritional factors due to limited information and lack of data on total daily cholesterol intake or level of saturated or trans-fatty acids, evaluation of dietary patterns (such as AHA 2020 ideal healthy diet or Mediterranean diet) may be more appropriate due to inconclusive evidence of an independent effect of macronutrient intake on outcomes.
In summary, this is the first national-level study to analyze adherence to health behavior stipulated by clinical guidelines (by the KSLA and IAS) in dyslipidemia patients according to awareness. In this study, awareness was not associated with adequate health behavior except for adequate carbohydrate intake in men found in subgroup analysis of dyslipidemia subjects without hypertension or diabetes. Although further studies are required to assess any temporal relationship between awareness and health behavior, development of procedures including counseling and education by healthcare providers could be considered to guide patients according to guidelines for optimal control of lipid levels and prevention of CVD. Furthermore, large-scale prospective cohort studies that can help define reliable and practical plans for the enhancement of healthy behavior for the management of dyslipidemia are needed.
Values are presented as mean (95% confidence interval) for age and lipid levels and % (95% confidence interval) for the remaining variables. All data were weighted to the Korean standard population. Data and P-values were obtained from t-test for continuous variables and chi-square test for categorical variables. Diagnosis of DM: fasting blood glucose ≥126 mg/dL, use of insulin or oral hypoglycemic agents. Diagnosis of HTN: average systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg, or taking medication for HTN.
DM, diabetes mellitus; HTN, hypertension; NA, not available.
*Less participants were available for analysis due to measurement methods (male: n=3,076, female: n=3,432).
Values are presented as % (95% confidence interval) or adjusted odds ratio (95% confidence interval), weighted to the Korean standard population. Crude proportions with P-values were obtained from chi-square tests, and logistic regression analysis was performed to examine the association between awareness of dyslipidemia and each health behavior with the adjustments specified. Model 1: adjusted for age; model 2: adjusted for age, obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, and household income; model 3: adjusted for age, obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, household income, prevalence of diabetes, and prevalence of hypertension.
BMI, body mass index.
*Statistically significant, P<0.05. †Excessive alcohol consumption: ≥3 standard drinks on ≥1 occasion in an average week. ‡Adequate physical activity: >150 minutes per week of moderate-intensity activity or >60 minutes per week of vigorous-intensity activity.
Values are presented as % (95% confidence interval) or adjusted odds ratio (95% confidence interval), weighted to the Korean standard population. Crude proportions with P-values were obtained from chi-square tests, and logistic regression analysis was performed to examine the association between awareness of dyslipidemia and each health behavior with the adjustments specified. Model 1: adjusted for age; model 2: adjusted for age, obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, and household income; model 3: adjusted for age, obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, household income, prevalence of diabetes, and prevalence of hypertension.
BMI, body mass index.
*Statistically significant, P<0.05. †Adequate intake of fiber: ≥25 g/d. ‡Adequate intake of carbohydrate: <65% of total calories per day. §Adequate intake of fat: <30% of total calories per day. ∥Adequate intake of protein: ≥15% of total calories per day.
Values are presented as % (95% confidence interval) or adjusted odds ratio (95% confidence interval), weighted to the Korean standard population. Crude proportions with P-values were obtained from chi-square tests, and logistic regression analysis was performed to examine the association between awareness of dyslipidemia and each health behavior with the adjustments specified. Model 1: adjusted for age; model 2: adjusted for age, obesity (body mass index ≥25 kg/m2), self-perceived health status, education, residential area, and household income.
*Statistically significant, P<0.05. †Excessive alcohol consumption: ≥3 standard drinks on ≥1 occasion in an average week. ‡Adequate physical activity: >150 minutes per week of moderate-intensity activity or >60 minutes per week of vigorous-intensity activity. §Adequate intake of fiber: ≥25 g/d. ∥Adequate intake of carbohydrate: <65% of total calories per day. ¶Adequate intake of fat: <30% of total calories per day. **Adequate intake of protein: ≥15% of total calories per day.
Values are presented as % (confidence interval) or adjusted odds ratio (95% confidence interval), weighted to the Korean standard population. Crude proportions with P-values were obtained from chi-square tests, and logistic regression analysis was performed to examine the association between awareness of dyslipidemia and each health behavior with the adjustments specified. Model 1: adjusted for age; model 2: adjusted for age, obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, and household income; model 3: adjusted for age, obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, household income, and hypertension.
BMI, body mass index.
*Excessive alcohol consumption: ≥3 standard drinks on ≥1 occasion in an average week. †Adequate physical activity: >150 minutes per week of moderate-intensity activity or >60 minutes per week of vigorous-intensity activity. ‡Adequate intake of fiber: ≥25 g/d. §Adequate intake of carbohydrate: <65% of total calories per day. ∥Adequate intake of fat: <30% of total calories per day. ¶Adequate intake of protein: ≥15% of total calories per day.
Values are presented as % (confidence interval) or adjusted odds ratio (95% confidence interval), weighted to the Korean standard population. Crude proportions with P-values were obtained from chi-square tests, and logistic regression analysis was performed to examine the association between awareness of dyslipidemia and each health behavior with the adjustments specified. Model 1: adjusted for age; model 2: adjusted for age and obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, and household income; model 3: adjusted for age, obesity (BMI ≥25 kg/m2), self-perceived health status, education, residential area, household income, and diabetes mellitus.
BMI, body mass index.
*Statistically significant: P<0.05. †Excessive alcohol consumption: ≥3 standard drinks on ≥1 occasion in an average week. ‡Adequate physical activity: >150 minutes per week of moderate-intensity activity or >60 minutes per week of vigorous-intensity activity. §Adequate intake of fiber: ≥25 g/d. ∥Adequate intake of carbohydrate: <65% of total calories per day. ¶Adequate intake of fat: <30% of total calories per day. **Adequate intake of protein: ≥15% of total calories per day.