Kevin W. Dodd

Estimation of Total Usual Calcium and Vitamin D Intakes in the United States

Our objective in this study was to estimate calcium intakes from food, water, dietary supplements, and antacids for U.S. citizens aged >or=1 y using NHANES 2003-2006 data and the Dietary Reference Intake panel age groupings. Similar estimates were calculated for vitamin D intake from food and dietary supplements using NHANES 2005-2006. Diet was assessed with 2 24-h recalls; dietary supplement and antacid use were determined by questionnaire. The National Cancer Institute method was used to estimate usual nutrient intake from dietary sources. The mean daily nutrient intake from supplemental sources was added to the adjusted dietary intake estimates to produce total usual nutrient intakes for calcium and vitamin D. A total of 53% of the U.S. population reported using any dietary supplement (2003-2006), 43% used calcium (2003-2006), and 37% used vitamin D (2005-2006). For users, dietary supplements provided the adequate intake (AI) recommendation for calcium intake for approximately 12% of those >or=71 y. Males and females aged 1-3 y had the highest prevalence of meeting the AI from dietary and total calcium intakes. For total vitamin D intake, males and females >or=71, and females 14-18 y had the lowest prevalence of meeting the AI. Dietary supplement use is associated with higher prevalence of groups meeting the AI for calcium and vitamin D. Monitoring usual total nutrient intake is necessary to adequately characterize and evaluate the populations nutritional status and adherence to recommendations for nutrient intake.

Physical activity and acculturation among adult hispanics in the United States

Understanding the prevalence and demographic correlates of physical activity is important for public health and epidemiological research. This analysis examines the association between acculturation and physical activity in a large (∼ 5,000) sample of Hispanic adults from the 2000 National Health Interview Survey. Scores for eight questions concerning language use were summed to produce an acculturation index. Factor analysis indicated that these questions assessed a single underlying construct. Self-reported adherence to recommendations concerning leisure time physical activity increased from 22.6% in the least acculturated tertile to 47% in the most acculturated tertile. In contrast, prevalence of walking or bicycling for errands decreased from 25.2 to 18.2%, and prevalence of standing or walking during most of the day decreased from 82.8 to 65.6% as acculturation increased. Thus, patterns of physical activity associated with leisure versus nonleisure time differed among Hispanics with varying acculturation levels. Alternatively, cultural factors may have differential effects on responses to questions concerning leisure and nonleisure time physical activity. In either case, assessing both types of activity is important for monitoring and understanding Hispanic health behaviors and interpreting epidemiological studies that involve physical activity in Hispanics.

Combining Information From Two Surveys to Estimate County-Level Prevalence Rates of Cancer Risk Factors and Screening

Cancer surveillance research requires estimates of the prevalence of cancer risk factors and screening for small areas such as counties. Two popular data sources are the Behavioral Risk Factor Surveillance System (BRFSS), a telephone survey conducted by state agencies, and the National Health Interview Survey (NHIS), an area probability sample survey conducted through face-to-face interviews. Both data sources have advantages and disadvantages. The BRFSS is a larger survey and almost every county is included in the survey, but it has lower response rates as is typical with telephone surveys and it does not include subjects who live in households with no telephones. On the other hand, the NHIS is a smaller survey, with the majority of counties not included; but it includes both telephone and nontelephone households, and has higher response rates. A preliminary analysis shows that the distributions of cancer screening and risk factors are different for telephone and nontelephone households. Thus, information from the two surveys may be combined to address both nonresponse and noncoverage errors. A hierarchical Bayesian approach that combines information from both surveys is used to construct county-level estimates. The proposed model incorporates potential noncoverage and nonresponse biases in the BRFSS as well as complex sample design features of both surveys. A Markov chain Monte Carlo method is used to simulate draws from the joint posterior distribution of unknown quantities in the model that uses design-based direct estimates and county-level covariates. Yearly prevalence estimates at the county level for 49 states, as well as for the entire state of Alaska and the District of Columbia, are developed for six outcomes using BRFSS and NHIS data from the years 1997–2000. The outcomes include smoking and use of common cancer screening procedures. The NHIS/BRFSS combined county-level estimates are substantially different from those based on the BRFSS alone.

Pregnancy Hormone Concentrations Across Ethnic Groups: Implications for Later Cancer Risk

A variety of in utero factors have been associated with risk of adult cancers, particularly birth weight, toxemia, and gestational age. These factors are thought to reflect hormonal exposures during pregnancy. We hypothesized that the prenatal hormonal milieu may explain part of the variation in cancer rates across ethnic groups, for example, the higher incidence of breast cancer in the Caucasian compared with Hispanic women and the higher incidence of prostate and lower incidence of testicular cancers among African-Americans compared with Caucasians. We measured hormones in early pregnancy blood samples from three ethnic groups in a health care plan in Boston, MA. Mean levels of androstenedione, testosterone, estrone, and prolactin were significantly lower in Caucasian women compared with Hispanic women. Although not statistically significant, estradiol levels were lower in Caucasian compared with Hispanic or African-American women. Concentrations of androstenedione, testosterone, and progesterone were notably higher in African-American compared with Caucasian or Hispanic women. These data are consistent with hypotheses that in utero hormonal exposures may explain some of the ethnic group differences in cancer risk.

Total folate and folic acid intakes from foods and dietary supplements of US children aged 1–13 y

BACKGROUNDnTotal folate intake includes naturally occurring food folate and folic acid from fortified foods and dietary supplements. Recent reports have focused on total folate intakes of persons aged > or =14 y. Information on total folate intakes of young children, however, is limited.nnnOBJECTIVEnThe objective was to compute total folate and total folic acid intakes of US children aged 1-13 y by using a statistical method that adjusts for within-person variability and to compare these intakes with the Dietary Reference Intake guidelines for adequacy and excess.nnnDESIGNnData from the 2003-2006 National Health and Nutrition Examination Survey, a nationally representative cross-sectional survey, were analyzed. Total folate intakes were derived by combining intakes of food folate (naturally occurring and folic acid from fortified foods) on the basis of 24-h dietary recall results and folic acid intakes from dietary supplements on the basis of a 30-d questionnaire.nnnRESULTSnMore than 95% of US children consumed at least the Estimated Average Requirement (EAR) for folate from foods alone. More than one-third (35%) of US children aged 1-13 y used dietary supplements, and 28% used dietary supplements containing folic acid. Supplement users had significantly higher total folate and folic acid intakes than did nonusers. More than half (53%) of dietary supplement users exceeded the Tolerable Upper Intake Level (UL) for total folic acid (fortified food + supplements) as compared with 5% of nonusers.nnnCONCLUSIONSnTotal folate intakes of most US children aged 1-13 y meet the EAR. Children who used dietary supplements had significantly higher total folate intakes and exceeded the UL by >50%.

Race/ethnic variation in serum levels of IGF-I and IGFBP-3 in US adults.

OBJECTIVESnThe IGF axis plays a significant role in normal growth and development and variation in IGFs is associated with health outcomes. Past studies report variation in IGF levels among race/ethnic groups known to differ in disease incidence. This paper reports on race/ethnic variation in serum levels of IGF-I and IGF-BP3 in a nationally representative and ethnically diverse sample of US adults.nnnDESIGNnSerum IGF-I and IGFBP-3 levels from the fasting subsample (n = 6061) of respondents to the US National Health and Nutrition Examination Survey III (NHANES III) were analyzed using an IGF-I ELISA (Diagnostic Systems Laboratory (DSL) 10-5600) and an IGFBP-3 IRMA (DSL 6600). The NHANES is a combined examination and interview survey of a nationally representative sample of US adults. Regression analyses were used to estimate cross-sectional associations between the IGF axis and demographic variables.nnnRESULTSnIn unadjusted analyses, serum IGF-I levels were higher in males than in females, and IGFBP-3 levels were higher in females than in males. Both analytes were lower in older adults. Univariate analyses indicate that serum levels of IGF-I are lower in female Non-Hispanic Whites (NHW) (256 [4.9]) and Hispanics (249 [6.6]) than in Non-Hispanic Blacks (NHB) (281 [4.9]). However, in males, IGF levels in NHWs (287 [3.6]) and NHBs (284 [4.3]) are similar and levels in Mexican-Americans are only moderately reduced (265 [3.4]). Notably, NHBs have the highest molar ratio of IGF-I:IGFBP-3 at all ages. After adjustment for age and BMI, gender and race/ethnicity differences persist.nnnCONCLUSIONSnThese cross-sectional data support exploration of the IGF axis as an explanation for some race/ethnic differences in cancer incidence.

Variability and Reproducibility of Circulating Vitamin D in a Nationwide U.S. Population

CONTEXTnMost studies examining associations between circulating vitamin D and disease are based on a single measure of vitamin D, which may not reflect levels over time, particularly because vitamin D concentrations vary by season. Few studies evaluated how well multiple 25-hydroxyvitamin D [25(OH)D] measures track within the same individual over time.nnnOBJECTIVEnThis study examined variability and reproducibility of vitamin D by evaluating repeat measurements of plasma 25(OH)D concentrations while accounting for determinants of circulating concentrations including dietary supplement use and latitude of residence from a population of U.S. radiologic technologists.nnnDESIGN AND PARTICIPANTSnWe analyzed circulating 25(OH)D in blood samples taken from 538 men and women from a prospective, nationwide study at two time points within a 1-yr period, most measured in different seasons. Inter- and intra-individual variability, reliability coefficients, and measurement error were examined.nnnRESULTSnThe spearman rank correlation between two measurements of 25(OH)D concentrations was moderate (r = 0.75, P < 0.001) and did not vary significantly by participant characteristics including age, race, or latitude. The intraclass correlation coefficient was 0.72 (95% confidence interval = 0.68-0.76). The deattenuation factor of plasma 25(OH)D levels was 1.39, suggesting that a single measure of vitamin D on a continuous scale in regression analyses may result in attenuated relationships of about 40%.nnnCONCLUSIONnOur results suggest that a single blood sample obtained in spring or fall provides a reasonable average for 25(OH)D over a 1-yr period, but additional studies are needed to estimate variability and agreement in plasma 25(OH)D measurements over longer intervals and younger populations.

No effect of meat, meat cooking preferences, meat mutagens or heme iron on lung cancer risk in the prostate, lung, colorectal and ovarian cancer screening trial†

Recent epidemiological studies have suggested that red and processed meat may increase the risk of lung cancer. Possible underlying mechanisms include mutagens produced during high‐temperature cooking or preservation, or formed endogenously from heme iron in meat. We used data from 99,579 participants of both screened and nonscreened arms of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, aged 55–74 years, to investigate whether meat type, cooking method, doneness level, intake of specific meat mutagens 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline (MeIQx), 2‐amino‐3,4,8‐trimethylimidazo[4,5‐f]quinoxaline] (DiMeIQx), 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP) and benzo(a)pyrene (B(a)P)] and heme iron are associated with lung cancer. Participants diet was assessed prospectively using a 124‐item food frequency questionnaire and an additional meat‐cooking module. Dietary data were used in conjunction with a database to estimate intake of MeIQx, DiMeIQx, PhIP, B(a)P and heme iron. After up to 8 years of follow‐up, 782 incident lung cancer cases were ascertained. Lung cancer risk was not associated with the consumption of either red (men: HRQ5 vs. Q1 = 1.11, 95% CI = 0.79–1.56, Ptrend = 0.42; women: HRQ5 vs. Q1 = 1.30, 95% CI = 0.87–1.95, Ptrend = 0.65) or processed meat (men: HRQ5 vs. Q1 = 1.12, 95% CI = 0.83–1.53, Ptrend = 0.22; women: HRQ5 vs. Q1 = 0.98, 95% CI = 0.68–1.41, Ptrend = 0.32) in multivariable models. High‐temperature cooking methods, level of meat doneness, meat mutagens and heme iron had no effect on lung cancer risk. In this population, we found no association between meat type, cooking method, doneness level or intake of specific meat mutagens or heme iron and lung cancer risk.

The Association of State Law to Physical Education Time Allocation in US Public Schools

OBJECTIVESnWe examined whether public schools in states with specific and stringent physical education (PE) laws, as assessed by the Physical Education-Related State Policy Classification System (PERSPCS), available on the Classification of Laws Associated with School Students (C.L.A.S.S.) Web site, reported more weekly PE time in the most recent School Health Policies and Programs Survey (SHPPS).nnnMETHODSnSchools (n=410) were grouped by their states PERSPCS time requirement scores (none, nonspecific requirement, or specific requirement). Average weekly school-level PE was calculated using the SHPPS-reported PE minutes. Weighted analyses determined if PE minutes/week differed by PERSPCS group.nnnRESULTSnSchools in states with specific requirement laws averaged over 27 and 60 more PE minutes/week at the elementary and middle school levels, respectively, compared with schools within states with nonspecific laws and over 40 and 60 more PE minutes per week, respectively, compared with elementary and middle schools in states with no laws. High school results were nonsignificant.nnnCONCLUSIONSnPublic health guidelines recommend at least 60 minutes of daily physical activity for children, and PE may further this goal. Strong codified law with specific time requirements for PE may be an important tool contributing toward adequate PE time and daily physical activity recommendations.

Physical activity and sedentary behavior in breast cancer survivors: New insight into activity patterns and potential intervention targets.

BACKGROUNDnInactivity and sedentary behavior are related to poorer health outcomes in breast cancer survivors. However, few studies examining these behaviors in survivors have used objective measures, considered activities other than moderate-to-vigorous intensity activity (MVPA) and/or sedentary behavior (i.e. low intensity activities) or compared survivors to healthy controls. The purpose of the present study is to compare accelerometer-measured activity of various intensities (total, light, lifestyle, MVPA) and sedentary behavior between breast cancer survivors and non-cancer controls.nnnMETHODSnAn imputation-based approach of independent sample t-tests adjusting for multiple comparisons was used to compare estimates of participation in each activity and sedentary behavior between survivors [n=398; M(SD)age=56.95 (9.11)] and block-matched non-cancer controls [n=1120; M(SD)age=54.88 (16.11)]. Potential moderating effects of body mass index (BMI), age, and education were also examined.nnnRESULTSnBreast cancer survivors registered less daily total (282.8 v. 346.9) light (199.1 v. 259.3) and lifestyle (62.0 v. 71.7) activity minutes and more MVPA (21.6 v. 15.9) and sedentary behavior (555.7 v. 500.6) minutes than controls (p<0.001 for all). These relationships were largely consistent across BMI, age and education. On average, survivors spent an estimated 66.4% of their waking time sedentary and 31.1% in light/lifestyle activity and 2.6% in MVPA.nnnCONCLUSIONSnBreast cancer survivors are more sedentary and participate in less low intensity activity than controls. Although survivors registered more MVPA, these levels were insufficient. Future research should explore these differences and potential benefits of targeting low intensity activities and reducing sedentary time in this population.