Muscle-bone Relationships in the Lower Leg of Healthy Pre-pubertal Females and Males

Muscle-bone relationships in healthy pre-pubertal children were investigated using four muscle measures as predictors of tibial strength: 66% tibia cross-sectional muscle area (CSMA) by pQCT; leg lean mass (LLM) by DXA; and muscle power (Power) and force (Force) measured during a two-footed jump. Polar strength strain index (pSSI), a calculated surrogate for bone strength at the 20% distal tibia, was obtained on 105 (54 male) self-assessed pre-pubertal children. The amount of muscle (CSMA, LLM) may influence bone strength more than muscle strength (Power, Force) during periods of rapid growth. Correlations and multiple regression partial-R values from models controlling for age, sex, height and weight were obtained for each muscle predictor. CSMA, LLM, Power and Force were positively correlated with pSSI (R=0.84, 0.92, 0.85; 0.66, respectively, all p\u3c 0.01). Partial-R values were highest for LLM (partial-R=0.21), similar for CSMA and Power (0.14, 0.15, respectively) and lowest for Force (0.04) in predicting pSSI. Muscle predictors were associated with total and cortical area (R=0.59 to 0.90; p\u3c 0.01 for all), but not cortical vBMD at the 20% distal tibia site. These data support relationships between muscle predictors and bone parameters measured by pQCT in healthy pre-pubertal children

Effect of Level of Farm Mechanization Early in Life on Bone Later in Life

OBJECTIVE: To determine whether an active rural lifestyle during childhood and adolescence, defined as low farm mechanization, was associated with bone measures later in life.METHODS: DXA bone data from total body, hip and spine, and pQCT data from 4% and 20% distal radius were obtained on 330 individuals (157 women) aged 20-66 years who farmed at least 75% of their lives. Primary bone outcomes included areal bone mineral density (aBMD), aBMD Z-scores, cortical and trabecular volumetric BMD, cortical thickness and periosteal circumference. Relationship between bone and recall of level of farm mechanization as a child was determined after stratifying by sex and controlling for covariates.RESULTS: Controlling for covariates, females from low mechanized farms had higher femoral neck (FN) bone area (p=0.03) than those on high or moderate mechanized farms. No group differences in pQCT ulna measurements or z-scores were found in either gender.CONCLUSION: A low farm mechanization level (high physical activity) prior to 20 years of age is associated with greater FN bone area in females. Future research that includes type and amount of physical activity performed will contribute to growing knowledge of how and when regular physical activity during childhood and adolescence affects adult bone health

Greater Polar Moment of Inertia at the Tibia in Athletes Who Develop Stress Fractures

Background: Several previous investigations have determined potential risk factors for stress fractures in athletes and military personnel. Purpose: To determine factors associated with the development of stress fractures in female athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 88 female athletes (cross-country, n ¼ 29; soccer, n ¼ 15; swimming, n ¼ 9; track and field, n ¼ 14; volleyball, n ¼ 12; and basketball, n ¼ 9) aged 18 to 24 years were recruited to participate in a longitudinal bone study and had their left distal tibia at the 4%, 20%, and 66% sites scanned by peripheral quantitative computed tomography (pQCT). Patients included 23 athletes who developed stress fractures during the following year (cases). Whole body, hip, and spine scans were obtained using dual-energy x-ray absorptiometry (DXA). Analysis of covariance was used to determine differences in bone parameters between cases and controls after adjusting for height, lower leg length, lean mass, fat mass, and sport. Results: No differences were observed between cases and controls in any of the DXA measurements. Cases had significantly greater unadjusted trabecular bone mineral content (BMC), greater polar moment of inertia (PMI) at the 20% site, and greater cortical BMC at the 66% site; however, after adjusting for covariates, the differences became nonsignificant. When analyses were repeated using all individuals who had ever had a stress fracture as cases (n ¼ 31) and after controlling for covariates, periosteal circumference was greater in the cases than the controls (71.1 ± 0.7 vs 69.4 ± 0.5 mm, respectively; P ¼ .04). Conclusion: A history of stress fractures is associated with larger bones. These findings are important because larger bones were previously reported to be protective against fractures and stress fractures, but study findings indicate that may not always be true. One explanation could be that individuals who sustain stress fractures have greater loading that results in greater periosteal circumference but also results in the development of stress fractures

Variation in Cortical Density Within the Cortical Shell of Individuals Across a Range in Densities and Ages

OBJECTIVES: The purpose of this study was to determine variability in cortical volumetric bone density (vBMD) from a single slice tibia image over a range of vBMD readings and ages. METHODS: Males and females (N=80; aged 6-80) were randomly selected from a previous study. Cortical vBMD at the anterior, posterior, medial, and lateral regions as well as the endocortical, mid-cortical, and pericortical regions of the cortical shell were determined using pQCT. RESULTS: Mean anterior ROI cortical vBMD (1111±11 mg/cm(3)) was lower than the posterior and lateral ROIs (1169±7 mg/cm(3) and 1151±9 mg/cm(3), respectively), (p CONCLUSIONS: Variability in cortical vBMD was higher among young individuals and those with lower overall cortical vBMD, while lowest in older individuals and men. The anterior ROI had lower mean cortical vBMD than posterior or lateral regions, and endocortical vBMD was lower than the mid- and pericortical regions

Experience Implementing a Public Health Surveillance System Designed for Fathers of Infants on a South Dakota American Indian Reservation

Introduction: Paternal behaviors and attitudes during pregnancy are not known. A health survey for fathers of recently born infants was developed to be administered concurrently with a maternal survey to assess parental behaviors and attitudes before, during and after pregnancy. Methods: Participants were parents of 149 American Indian infants born from April 1 and Dec. 31, 2015 who were recruited prospectively from data of all births in prespecified reservation counties representing Sisseton Wahpeton Oyate of the Lake Traverse Reservation. Data collection was via hard-copy or online survey. Results: Response rate among mothers was 62 percent (n=92). Of 149 births, 126 listed a father on the birth certificate and 51 percent (n=64) of these completed surveys on average 4.7 months post-birth. Healthwise, 90 percent of fathers reported being overweight or obese, but a small percent visited a health care worker in the previous year to be checked for diabetes (11 percent) or hypertension (14 percent). Among fathers who smoked in the last two years (73 percent), 77 percent of the mothers also smoked compared to 20 percent of mothers smoking if the father did not smoke (pConclusion: Conducting a health survey with both fathers and mothers in a reservation setting is feasible and the father’s attitudes and behaviors related to breastfeeding and smoking were associated with maternal health behaviors. Most fathers attended health care visits with the mother, but they were not being screened for health conditions despite a large proportion being overweight and smokers. Prenatal and antenatal visits may provide an opportune time to engage fathers and address paternal health issues

Cross-Sectional and Longitudinal Association between Glycemic Status and Body Composition in Men: A Population-Based Study

This study sought to evaluate the associations between changes in glycemic status and changes in total body (TB), trunk, and appendicular fat (FM) and lean mass (LM) in men. A population-based study of men aged 20–66 years at baseline were included in cross-sectional (n = 430) and three-year longitudinal (n = 411) analyses. Prediabetes was defined as fasting glucose 100–125 mg/dL. Type 2 diabetes (T2D) was determined by: self-reported diabetes, current anti-diabetic drug use (insulin/oral hypoglycemic agents), fasting glucose (≥126 mg/dL), or non-fasting glucose (≥200 mg/dL). Body composition was evaluated by dual-energy X-ray absorptiometry. Longitudinal analyses showed that changes in TB FM and LM, and appendicular LM differed among glycemic groups. Normoglycemic men who converted to prediabetes lost more TB and appendicular LM than men who remained normoglycemic (all, p \u3c 0.05). Normoglycemic or prediabetic men who developed T2D had a greater loss of TB and appendicular LM than men who remained normoglycemic (both, p \u3c 0.05). T2D men had greater gains in TB FM and greater losses in TB and appendicular LM than men who remained normoglycemic (all, p \u3c 0.05). Dysglycemia is associated with adverse changes in TB and appendicular LM

South Dakota Pregnancy Survey 2016 Data Report

The South Dakota Department of Health, in conjunction with the EA Martin Program at South Dakota State University, conducted a 2016 Pregnancy Risk Assessment Monitoring System (PRAMS)-like surveillance project. The 2016 South Dakota PRAMS-like survey was a statewide population-based survey based on a stratified random sample of women who gave birth to a live-born infant, thereby allowing rates to be estimated for South Dakota mothers giving birth in 2016. The topics included in this survey were selected to enhance our understanding of maternal attitudes and behaviors around the time of pregnancy and the weighted response rate was 67.6%

Fat Mass Gain is Lower in Calcium-supplemented than in Unsupplemented Preschool Children with Low Dietary Calcium Intakes

BACKGROUND: Dietary calcium may play a role in the stimulation of lipolysis and the inhibition of lipogenesis, thereby reducing body fat.OBJECTIVE: The aim was to determine whether an association existed between change in percentage body fat (%BF) or fat mass and calcium intake in children aged 3-5 y.DESIGN: A secondary analysis of a 1-y randomized calcium and activity trial in 178 children was conducted. Three-day diet records and 48-h accelerometer readings were obtained at 0, 6, and 12 mo. Body composition was measured by dual-energy X-ray absorptiometry at 0 and 12 mo.RESULTS: The decrease in %BF was less in girls (-0.6 +/- 2.8%) than in boys (-1.5 +/- 2.6%; P = 0.03) and correlated with age (r = 0.19, P = 0.01) and maternal body mass index (r = 0.19, P = 0.02). Changes in fat mass were not significantly different by activity group or between children randomly assigned to receive calcium or placebo (0.5 +/- 0.9 and 0.6 +/- 0.8 kg, respectively; P = 0.32). Similar findings were observed for the change in %BF. No correlations between %BF and fat mass changes and dietary calcium (r = -0.01, P = 0.9 and r = -0.05, P = 0.5) or total (dietary + supplement) calcium intake (r = -0.02, P = 0.8 and r = -0.06, P = 0.4) were observed. Among children in the lowest tertile of dietary calcium (/d), fat mass gain was lower in the calcium group (0.3 +/- 0.5 kg) than in the placebo group (0.8 +/- 1.1 kg) (P = 0.04) but was not correlated with mean total calcium intake (r = -0.20).CONCLUSION: These findings support a weak relation between changes in fat mass gain and calcium intake in preschool children, who typically consume below recommended amounts of dietary calcium

Rural vs. Non-rural Differences and Longitudinal Bone Changes by DXA and pQCT in Men Aged 20-66 Years: A Population-Based Study

The purpose of this research was to determine whether there were differences in estimated means and rates of change in BMC, bone area, BMD and measures of bone geometry among men (n=544) from three distinct populations (Hutterite [rural], rural non-Hutterite, non-rural), and whether activity levels or calcium intake explain these population differences. Men were enrolled in the South Dakota Rural Bone Health Study and followed for 7.5 years to estimate means and rates of change in bone mass, density, size and geometry. Femoral neck (FN) and spine measurements were obtained every 18 months by DXA and distal radius (4% and 20%) measurements by pQCT. Activity measurements and calcium intake were obtained quarterly for the first 3 years and at 54, 72, and 90 months. Rural men had greater percent time in moderate plus vigorous activity (mean ± SD: 22 ± 10 vs. 15 ± 8%,