2 markers of obesity included maternal body mass index, childhood growth patterns (early rapid growth and early adiposity rebound), childhood obesity, and father’s employ- ment (a proxy measure for socioeconomic status [SES] in many studies). Other recent studies have examined the rela- tionship between prenatal exposures such as smoking during pregnancy and early feeding practices (e.g., breastfeeding, early introduction of solid foods) and adverse cardiovascular health outcomes in preschool age children [7, 8]. Results of these studies showed that maternal smoking during pregnancy was associated with a higher body mass index (BMI) at four years of age in children with a normal birth weight and in those who were small for gestational age at birth [7] and that shorter breastfeeding duration and exclusivity (no formula or solid food) during the ﬁrst 6 months tended to be associated with increased growth rates for length, weight and BMI between the age of 3 and 6 months but not with the risks of overweight and obesity until the age of 3 years [8]. Early childhood is an important stage of growth to examine given that one in four US children under age 5 is either overweight (≥85th to <95th age- and sex-adjusted percentiles for BMI) or obese (≥95th age- and sex-adjusted percentiles for BMI) [9, 10]. Overweight preschool-age children are ﬁve times more likely to be overweight during adolescence and more than four times as likely to become obese as adults than are their normal-weight counterparts [11]. Recent studies have shown that obesity in this age range is associated with cardiovascular disease risk factors and varies by ethnic group [12]. The concern is that childhood overweight will contribute to the earlier onset of overall morbidity and mortality in adulthood, making early intervention crucially important [4, 5]. Preschool children are at an ideal age to examine these relationships because there are fewer exposures to envi- ronmental confounders and interactions compared to older children and adults when it might be much more challenging to distinguish the contribution of the environment versus physiology. The relationship between overweight/obesity, cardiovascular disease (CVD) risk factors and birthweight, mother’s smoking status during pregnancy, breastfeeding, and early introduction of solids and how these relation- ships vary by ethnic group speciﬁcally is largely unknown. Therefore, we assessed these relationships in a population- based multiethnic sample of 3-to-6-year-olds to determine the inﬂuence of breastfeeding, early introduction of solid foods, smoking during pregnancy, and low birth weight on the prevalence of CVD risk factors. 2. Methods 2.1. Study Population. The periodic National Health and Nutrition Examination Survey (NHANES) uses a stratiﬁed, multistage probability design to capture a representative sample of the civilian, noninstitutionalized US population [13]. This design allows survey results from two or more periods to be combined to increase the sample size and analytic options. Each 2-year period, and any combination International Journal of Pediatrics of 2-year periods, is a nationally representative sample. To produce estimates with greater statistical reliability for demo- graphic subgroups and rare events, combining two or more 2-year periods of the survey results is strongly recommended [13]. Therefore, for this study, NHANES data ﬁles for 1999- 2000, 2001-2002, 2003-2004, 2005-2006, and 2007-2008 were combined to form a single analytic ﬁle. 2.2. Eligibility Criteria. From the above-cited NHANES 1999–2008 data ﬁle all Non-Hispanic White (NHW), His- panic (Mexican American, other Hispanic groups com- bined), and Non-Hispanic Black (NHB) boys and girls aged 3 to 6 years and their mothers were included. The following measurements were available for analysis in this age group: age, sex, ethnicity, height and weight (for BMI), WC, C-reactive protein (CRP), total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) choles- terol, and triglycerides (available in the morning-only ran- domized subsample). Using data on response rates found on the CDC website [14], we estimated the total number of 3-to-6-year-old children who were screened in the surveys from 1999– 2008 to be 4,627. Of the children screened, 4,091 (88%) participated in the interview and 3,876 (84%) participated in the examination. We eliminated 225 children who were in the “other” ethnic group category (not Hispanic, NHW or NHB) and another 7 children who were diabetic or on metabolic altering drugs; therefore, our analytic sample included 3,644 children (79% of children screened). With a sample size of more than 1000 in each ethnic group (Table 2), it is possible to detect a small eﬀect size of 0.20 at the two-tailed 0.05 level with 80% power [15]. 2.3. Measures and Data Collection. Persons selected to partic- ipate in the NHANES survey were invited to be interviewed in their homes. Household interview data were collected with computer-assisted personal interviewing procedures and included demographic, socioeconomic, dietary, and health- related information. Because the children were so young (less than 7 years old), the mothers answered all questions on their behalf. Mothers were asked questions about their pregnancy with the index child included in this analysis. Speciﬁcally included were the responses regarding self-reported smoking status during pregnancy, infant birthweight, whether the infant was breastfed, and if solid foods were introduced in the infant’s diet before six months of age. After the interview, each child received a standardized physical examination at a local Medical Examination Center. Laboratory and anthropometric measurement methods used at the Medical Examination Centers are described in The NHANES Laboratory/Medical Technologists Procedures Manual. [16] Brieﬂy, anthropometric measures taken during the standardized examination consisted of barefoot standing height (with a stadiometer), weight with minimal clothing (on a digital, electronic scale) [1], and waist circumference (in the horizontal plane at a point marked just above the right