Coronary heart disease (CHD) is the leading cause of death in the United States, accounting for 27% of all deaths in 2005 (1). An established body of evidence points to reducing low-density lipoprotein (LDL) cholesterol as one of the most effective ways to prevent and treat CHD, regardless of a person's risk (2-4). On average, every 1% reduction in LDL cholesterol is matched by a 1% reduction in the likelihood of a major cardiac event (5). Thus, small reductions in population LDL cholesterol could prevent many CHD-related deaths.

Despite advances in lowering total blood cholesterol, particularly throughout the 1980s (6,7), and the recent broad-scale use of medications targeting LDL cholesterol, control of lipid levels remains poor in the United States. Prevalence of high total cholesterol and high LDL cholesterol remained virtually unchanged between 1988-1994 and 1999-2004 (8,9), and only one-fourth of US adults with elevated LDL cholesterol have their condition appropriately controlled (8). Blacks and Mexican Americans are less likely than whites to take drugs from the statin class, and they have poorer control (8,10). National estimates of high LDL cholesterol are not available for other Hispanics or for Asians.

Local monitoring of the prevalence, treatment, and control of CHD risk factors is needed for planning and evaluating interventions to prevent disease. Previous studies suggest that New York City is similar to or better than the rest of the country in terms of prevalence and management of some CHD risk factors (hypertension and obesity) (11,12) but worse for others (diabetes) (12,13). However, no study has examined LDL cholesterol levels by using a representative sample in New York City or in any exclusively urban setting. In this study, we examine prevalence, awareness, treatment, and control of high LDL cholesterol in New York City adults by using the first community Health and Nutrition Examination Survey (NYC HANES). To define high LDL levels, we used the National Cholesterol Education Program Adult Treatment Panel III (ATP III) guidelines, which provide thresholds for diagnosing and targets for lowering high LDL cholesterol on the basis of individual CHD risk (5,14). Findings on variation in LDL cholesterol levels in this population may be useful for researchers and policy makers in other urban environments.

NYC HANES is a population-based, cross-sectional, examination survey of noninstitutionalized New York City adult residents aged 20 years or older. A 3-stage cluster sampling design was used to recruit participants from June through December 2004. Detailed study methods are published elsewhere (15). The survey consisted of personal interviews, physical examinations, and laboratory testing. All survey instruments, protocols, and measurements were standardized to National Health and Nutrition Examination Survey (NHANES) specifications. Lipid profiles were analyzed at the Lipoprotein Analytical Laboratory at Johns Hopkins University Hospital. Most laboratories that perform testing for NHANES were used for NYC HANES (16).

The NYC HANES protocol was approved by the New York City Department of Health and Mental Hygiene and the New York State Department of Health institutional review boards. Study participants provided written, informed consent.

A total of 3,047 eligible participants were identified (84% household contact rate); 1,999 completed the face-to-face interview and at least 1 examination measurement (66% participant response rate), yielding an overall response rate of 55%. Of the 1,999 participants, valid high-density lipoprotein (HDL) and total cholesterol measurements were obtained for 1,783 participants. A random sample of participants (80%) was assigned to fast for at least 8 hours before giving blood, and of these, valid measurements were available for 1,150 participants. An additional 136 participants not assigned to fast but who did voluntarily were similar to those assigned to fast for all demographic characteristics except age and were included in the sample. Valid LDL cholesterol data were available for 1,286 participants.

This study documents the large burden of high LDL cholesterol in New York City. We found that more than 1 in 4 New York City adults have high LDL cholesterol, placing them at elevated risk for CHD (2,3). This proportion is similar to national levels (8).

We also found that nearly one-third of New York City adults with high LDL cholesterol were unaware of their condition. Among those who were aware, less than two-thirds were taking cholesterol-lowering medications and less than half had their LDL cholesterol under control, suggesting that adults in New York City are not adequately treated. We found particularly low levels of treatment and control among those in the highest CHD risk groups, and low levels of control among black and Hispanic populations. Intensive efforts are needed to reduce LDL cholesterol among these groups (4).

Lower awareness and treatment rates may be due in part to providers' use of guidelines other than the 2004 ATP III. Providers who use the US Preventive Services Task Force (USPSTF) guidelines would not screen low-risk men before age 35 or women before age 45 (21). ATP III recommends screening all adults from age 20, every 5 years. Using USPSTF guidelines, 16% of those we defined as unaware of high LDL cholesterol would not have been routinely screened. Similarly, low rates of treatment in the high-risk group may be due to limited provider adoption of the 2004 ATP III guidelines, which reduced the threshold for drug therapy in the high-risk group from ≥130 mg/dL to ≥100 mg/dL. However, using the former threshold of 130 mg/dL for the high-risk group results in a similarly low treatment rate of 69.0% among those who were aware of having high LDL cholesterol.

Our analysis of the distribution of mean LDL cholesterol found similar levels between New York City and the United States, but a higher mean LDL cholesterol among foreign-born adults in New York City than among foreign-born adults in the United States overall. Foreign-born adults make up more than one-third (36.7%) of New York City's population (compared with 12.5% of the US population) (22). The higher mean in New York City may be due to differences in the racial/ethnic diversity in the NYC HANES foreign-born population (22% white, 18% black, 19% Asian, 39% Hispanic, and 2% "other") compared with the NHANES foreign-born population (27% white, 7% black, 28% Mexican American, 18% other Hispanic, and 21% "other/multiracial").

This study builds on previous NHANES studies by measuring LDL cholesterol among Hispanics and Asians, which could not be assessed in prior national surveillance data, and a closer examination of the foreign-born. New York City Hispanics had particularly low levels of awareness compared with whites, possibly because of less access to care. Lack of insurance was associated with lower awareness levels. Diagnosis of high cholesterol requires a blood test, and treatment requires ongoing monitoring, costs of which can be barriers for people without insurance coverage. Also of concern is the disparity in control rates between foreign- and US-born adults who are treated with medication. These findings support the need to identify and respond to health disparities (23) to ensure increased access to health care for all groups.

The high prevalence of high LDL coupled with poor levels of control suggests that effective strategies to reduce cholesterol requires a multilevel approach that includes and goes beyond the clinic. Population approaches to prevent and reduce high LDL cholesterol offer opportunities to reduce risk across all risk groups (24).

Our findings are consistent with those of other studies that associated overweight or obesity and smoking with high LDL cholesterol (25,26) and underscore the need for policies that improve the food environment and reduce smoking. New York City has introduced such population-based initiatives. These include restricting the use of artificial trans fat in restaurants (27), increasing the number of mobile vendors that sell vegetables, and setting nutrition standards for foods purchased by New York City agencies. Such policies aim to normalize heart-healthy eating and represent a promising strategy to reduce cholesterol levels and CHD risk (24). Smoking prevalence is dramatically lower in New York City (28) after an increase in local and state cigarette taxes (making them among the most expensive in the country), hard-hitting antitobacco advertising, and wide distribution of free nicotine patches and gum (29). Federal action to extend similar and other effective policies across the country are needed for widespread reductions in LDL cholesterol.

In addition to environment change approaches, improved clinical approaches to diagnosis and management of high LDL cholesterol are needed. Studies have demonstrated that delayed initiation of treatment for high LDL is common, despite evidence that early initiation and longer duration of therapy mitigates the atherosclerotic process (30). Once initiated, medication therapy is often not aggressive enough to reach targets because of providers' concerns about adverse effects, tolerance, and patient adherence to specific medications (31). The introduction of panel management in primary care practices is an emerging proactive systematic approach to improve care, for example, by identifying a list of the provider's patients with poorly controlled LDL for individualized outreach and follow-up by the health care team (32).

Limitations of the study include recall bias and measurement error associated with self-report. The study strictly adhered to quality assurance procedures from NHANES to limit response bias. Poststratification weighting on the basis of age group, sex, race/ethnicity, and borough was applied to decrease the effect of component and item nonresponse. Additional analyses of treatment and control of LDL cholesterol within specific subgroups may have provided a deeper understanding of disparities but were limited by sample size.

An unacceptably large proportion of the New York City population has high or uncontrolled LDL cholesterol. New York City adults who are at the greatest risk for CHD need aggressive medical intervention to reduce their LDL cholesterol levels. On a broader level, programs that address primary prevention of high cholesterol through changes in the food environment and tobacco policies can prevent CHD-related illness and death and reduce health disparities.