Sensory-based food education in early childhood education and care, willingness to choose and eat fruit and vegetables, and the moderating role of maternal education and food neophobia.

OBJECTIVE: To investigate the association between sensory-based food education implemented in early childhood education and care (ECEC) centres and children's willingness to choose and eat vegetables, berries and fruit, and whether the mother's education level and children's food neophobia moderate the linkage. DESIGN: The cross-sectional study involved six ECEC centres that provide sensory-based food education and three reference centres. A snack buffet containing eleven different vegetables, berries and fruit was used to assess children's willingness to choose and eat the food items. The children's parents completed the Food Neophobia Scale questionnaire to assess their children's food neophobia. SETTING: ECEC centres that provide sensory-based food education and reference ECEC centres in Finland. SUBJECTS: Children aged 3-5 years in ECEC (n 130) and their parents. RESULTS: Sensory-based food education was associated with children's willingness to choose and eat vegetables, berries and fruit. This association was stronger among the children of mothers with a low education level. A high average level of neophobia in the child group reduced the children's willingness to choose vegetables, berries and fruit. No similar tendency was observed in the group that had received sensory-based food education. Children's individual food neophobia had a negative association with their willingness to choose and eat the vegetables, berries and fruit. CONCLUSIONS: Child-oriented sensory-based food education seems to provide a promising method for promoting children's adoption of vegetables, berries and fruit in their diets. In future sensory food education research, more focus should be placed on the effects of the education at the group level.

Associations of disordered sleep with body fat distribution, physical activity and diet among overweight middle-aged men.

This cross-sectional study aimed to investigate whether body fat distribution, physical activity levels and dietary intakes are associated with insomnia and/or obstructive sleep apnea among overweight middle-aged men. Participants were 211 Finnish men aged 30-65 years. Among the 163 overweight or obese participants, 40 had insomnia only, 23 had obstructive sleep apnea only, 24 had comorbid insomnia and obstructive sleep apnea and 76 were without sleep disorder. The remaining 48 participants had normal weight without sleep disorder. Fat mass, levels of physical activity and diet were assessed by dual-energy X-ray densitometry, physical activity questionnaire and 3-day food diary, respectively. Among the overweight participants, we found that: (i) groups with sleep disorders had higher fat mass in trunk and android regions than the group without sleep disorder (P = 0.048-0.004); (ii) the insomnia-only group showed a lower level of leisure-time physical activity (436.9 versus 986.5 MET min week(-1) , P = 0.009) and higher intake of saturated fatty acids (14.8 versus 12.7 E%, P = 0.011) than the group without sleep disorder; and (iii) the comorbid group had a lower level of leisure-time physical activity (344.4 versus 986.5 MET min week(-1) , P = 0.007) and lower folate intake (118.9 versus 152.1 µg, P = 0.002) than the group without sleep disorder, which were independent of body mass index. The results suggest that central obesity is associated with insomnia and/or obstructive sleep apnea. In addition, low levels of leisure-time physical activity and poor dietary intakes are related to insomnia or comorbid insomnia and obstructive sleep apnea among overweight men.

Women with and without metabolic disorder differ in their gut microbiota composition.

The aim of this study was to investigate whether overweight/obese women in metabolic disorder group (MDG, n = 27) differ in their gut microbiota composition from overweight/obese women in non-metabolic disorder group (NMDG, n = 47) and normal weight women group (NWG, n = 11). Gut microbiota was profiled from fecal samples by 16S rRNA fluorescence in situ hybridization and flow cytometry in 85 premenopausal women. Body composition was measured by bioimpedance, and dietary intakes were collected via food diaries. Standard procedures were used to assess plasma glucose, serum insulin, lipids, and inflammatory status. We found that the proportion of bacteria belonging to Eubacterium rectale-Clostridium coccoides group, indicating efficient energy harvest from nutrients in gut, was higher in MDG compared to NMDG and NWG, while no difference was found between NMDG and NWG. The proportion of Eubacterium rectale-Clostridium coccoides group correlated positively with weight, BMI, total fat, fat mass percentage (FM%), visceral fat area, and serum triglycerides, and negatively with high-density lipoprotein (HDL). Our results indicate that certain members of Eubacterium rectale-Clostridium coccoides group are associated with obesity-related MDs not obesity per se.

Prolonged breast-feeding protects mothers from later-life obesity and related cardio-metabolic disorders.

OBJECTIVE: To investigate the long-term effects of duration of postpartum lactation on maternal body composition and risk for cardio-metabolic disorders in later life. DESIGN: Retrospective study. Body composition was measured using dual-energy X-ray absorptiometry and serum glucose, insulin and lipids were analysed using enzymatic photometric methods 16-20 years after the last pregnancy. Medical history and lifestyle factors were collected via a self-administered questionnaire. Detailed information regarding weight change patterns during each pregnancy was obtained from personal maternity tracking records. SETTING: City of Jyväskylä and surroundings in Central Finland. SUBJECTS: Two hundred and twelve women (mean age 48, range 36-60 years). RESULTS: At 16-20 years after their last pregnancy, women who had breast-fed for less than 6 months had higher total body fat mass and fat mass percentage, particularly in the android region (46·5 (sd 8·2) %) than mothers who had breast-fed for longer than 6 months (39·0 (sd 10·2) %) or for longer than 10 months (38·4 (sd 10·9) %, P < 0·01). These differences were independent of pre-pregnancy weight and BMI, menopausal status, smoking status, level of education, participation in past and present leisure-time physical activity, and current dietary energy intake. Higher body fat mass was also associated with higher fasting serum glucose concentration and insulin resistance, TAG, LDL cholesterol and total cholesterol concentrations, as well as higher systolic and diastolic blood pressure (P < 0·05 for all). CONCLUSIONS: Short duration of breast-feeding may induce weight retention and fat mass accumulation, resulting in increased risk of cardio-metabolic disorders in later life.

Concerted actions of insulin-like growth factor 1, testosterone, and estradiol on peripubertal bone growth: a 7-year longitudinal study.

A better understanding of how bone growth is regulated during peripuberty is important for optimizing the attainment of peak bone mass and for the prevention of osteoporosis in later life. In this report we used hierarchical models to evaluate the associations of insulin-like growth factor 1 (IGF-1), estradiol (E(2) ), and testosterone (T) with peripubertal bone growth in a 7-year longitudinal study. Two-hundred and fifty-eight healthy girls were assessed at baseline (mean age 11.2 years) and at 1, 2, 3.5, and 7 years. Serum concentrations of IGF-1, E(2) , and T were determined. Musculoskeletal properties in the left lower leg were measured using peripheral quantitative computed tomography (pQCT). Serum levels of IGF-1, E(2) , and T increased dramatically before menarche, whereas they decreased, plateaued, or increased at a lower rate, respectively, after menarche. IGF-1 level was positively associated with periosteal circumference (PC) and total bone mineral content (tBMC) throughout peripuberty but not after adjustment for muscle cross-sectional area (mCSA). On the other hand, IGF-1 was associated with tibial length (TL) independently of mCSA before menarche. T was positively associated with TL, PC, tBMC, and cortical volumetric bone mineral density, independent of mCSA, before menarche but not after. E(2) was associated with TL positively before menarche but negatively after menarche. These findings suggest that during puberty, circulating IGF-1 promotes bone periosteal apposition and mass accrual indirectly, probably through stimulating muscle growth, whereas the effects of sex steroids on bone growth differ before and after menarche, presenting a biphasic pattern. Hence the concerted actions of these hormones are essential for optimal bone development in peripuberty.

Effect of long-term leisure time physical activity on lean mass and fat mass in girls during adolescence.

The purpose of this 7-yr prospective longitudinal study was to examine if the level and consistency of leisure-time physical activity (LTPA) during adolescence affected the quantity and distribution of lean mass (LM) and fat mass (FM) at early adulthood. The study subjects were 202 Finnish girls who were 10-13 yr old at baseline. LM and FM of the total body (TB), arms, legs, and trunk were assessed by dual-energy X-ray absorptiometry. Muscle cross-sectional area (mCSA) of the left leg was assessed by peripheral quantitative computed tomography. Scores of LTPA were obtained by questionnaire. Girls were divided into four groups comprising those with consistently low (G(LL)) or consistently high (G(HH)) physical activity, or those whose physical activity changed from low to high (G(LH)), or from high to low (G(HL)), over the 7 yr of follow-up. At baseline, no differences were found in LM, FM, and FM% among the groups in any of the body segments. By the end of the study G(HH) and G(LH) had higher values of LM of the TB, arms, legs, and trunk than that of the G(HL) and G(LL) groups (P < 0.05, respectively). High FM% of the TB was associated with low level of LTPA, but no significant differences were found in the absolute amount of FM and mCSA among the LTPA groups. Our results suggest that a consistently high level of LTPA during the transition from prepuberty to early adulthood has a positive effect on lean mass gain in girls. Participating in 5 h of LTPA per week had a significant effect on FM% but not on the absolute amount of fat mass.

Leisure-time physical activity and nutrition: a twin study.

OBJECTIVE: To determine the association between long-term leisure-time physical activity/inactivity and eating behaviours in twin pairs discordant for physical activity for 30 years. DESIGN: Co-twin control design with cross-sectional data collection using questionnaire on eating habits and 5 d food diary. Differences in eating behaviours between physically active and inactive co-twins were analysed with pairwise tests. SETTING: Finland. SUBJECTS: Sixteen same-sex twin pairs (seven monozygotic and nine dizygotic, mean age 60 years) discordant for physical activity, selected from the Finnish Twin Cohort on the basis of physical activity discordance for 30 years, blinded to their possible differences in eating behaviours. RESULTS: The eating habits questionnaire revealed that physically active co-twins more frequently reported that it is easy to eat according to need, whereas overeating and/or restrictive eating was more common among the inactive co-twins (P = 0·035). Avoiding calories was more common among the active than inactive co-twins (P = 0·034). Based on food diaries the physically active co-twins had daily energy intake on average 15·5 kJ/kg higher than their inactive co-twins (P = 0·030). The active co-twins also had a higher intake of vitamin C (P = 0·004), total water (P = 0·044), legumes and nuts (P = 0·015) and sweets (P = 0·036), as well as a lower energy-adjusted intake of meat (P = 0·013). CONCLUSIONS: The physically active persons seem to eat more but not necessarily healthier food. However, habitual physical activity may help in eating according to need and in reaching and maintaining a healthy body composition. Therefore, it is necessary to incorporate both dietary and physical activity advice into health counselling.

Familial resemblance and diversity in bone mass and strength in the population are established during the first year of postnatal life.

Familial resemblance and diversity in bone structure and strength in adulthood are determined in part during growth. Whether these characteristics are established during gestation or shortly after birth is not known. Total-body, lumbar spine, and femoral neck size and mass and indices of tibial bending strength and distal radial compressive strength were measured using bone densitometry and quantitative computed tomography in 236 girls at 18.5 years of age. Among them, 219, 141, and 105 girls had crown-heel length (CHL) and weight recorded at birth and at 6 and 12 months of age, and then height and weight were recorded at 3, 5, 10, 13, and 15 years of age in 181, 176, 127, 111, and 228 girls, respectively. Of these girls, 101 and 93 girls also had bone structure assessed at 11 and 13 years of age, respectively. Similar bone measurements were made once in 78 mother-father pairs. CHL and weight at birth did not correlate or did so weakly with bone traits in girls at 18 years of age. By contrast, CHL at 6 months correlated with the height, bone traits, and strength at puberty and at 18 years of age (r = 0.24-0.56, p < .001) in girls and with their parents' height and bone traits (r = 0.15-0.37, p < .05). When the girls' CHL at 6 months was stratified into quartiles, the absolute and relative differences in bone traits observed at puberty (approximately 11.5 years) were maintained as these traits tracked during the ensuing 7 years. Similarly, weight at 6 months correlated with the girls' bone traits at puberty and 18 years of age (r = 0.22-0.55, p < .05). During puberty and at 18 years of age, the girls' bone traits correlated with the corresponding traits in their parents (r = 0.32-0.43, p < .01). It is concluded that familial resemblance in bone structural strength and the position of an individual's bone traits relative to others in adulthood are likely to be established during the first year of life. Thus susceptibility to bone fragility late in life has its antecedents established early in life.

Long-term leisure-time physical activity has a positive effect on bone mass gain in girls.

The purpose of this 7-year prospective longitudinal study was to examine whether the level and consistency of leisure-time physical activity (LTPA) during adolescence affected the bone mineral content (BMC) and bone mineral density (BMD) attained at early adulthood. The study subjects were 202 Finnish girls who were 10 to 13 years of age at baseline. Bone area (BA), BMC, and BMD of the total body (TB), total femur (TF), and lumbar spine (L(2)-L(4)) were assessed by dual-energy X-ray absorptiometry (DXA). Scores of LTPA were obtained by questionnaire. Girls were divided into four groups: consistently low physical activity (G(LL)), consistently high (G(HH)), and changed from low to high (G(LH)) and from high to low (G(HL)) during 7 years of follow-up. At baseline, no differences were found in BA, BMC, and BMD among the groups in any of the bone sites. Compared with the G(LL) group, the G(HH) group had higher BMC (11.7% in the TF, p < .05) and BMD at the TB (4.5%) and the TF (12.2%, all p < .05) at age 18. Those in the G(LH) group also had higher a BMC at each site (8.5% to 9.4%, p < .05) and a higher BMD in the TB (5.4%) and the TF (8.9%) than that of G(LL) (all p < 0.05) at the age 18. Our results suggest that long-term leisure-time physical activity has a positive effect on bone mass gain of multiple bone sites in girls during the transition from prepuberty to early adulthood. In addition, girls whose physical activity increases during adolescence also benefit from bone mass gain.

Low volumetric BMD is linked to upper-limb fracture in pubertal girls and persists into adulthood: a seven-year cohort study.

The aetiology of increased incidence of fracture during puberty is unclear. This study aimed to determine whether low volumetric bone mineral density (vBMD) in the distal radius is associated with upper-limb fractures in growing girls, and whether any such vBMD deficit persists into adulthood. Fracture history from birth to 20 years was obtained and verified by medical records in 1034 Finnish girls aged 10-13 years. Bone density and geometry at distal radius, biomarkers and lifestyle/behavioural factors were assessed in a subset of 396 girls with a 7.5-year follow-up. We found that fracture incidence peaked during puberty (relative risk 3.1 at age of 8-14 years compared to outside this age window), and 38% of fractures were in the upper-limb. Compared to the non-fracture cohort, girls who sustained upper-limb fracture at ages 8-14 years had lower distal radial vBMD at baseline (258.9+/-37.5 vs. 287.5+/-34.1 mg/cm(3), p=0.001), 1-year (252.0+/-29.3 vs. 282.6+/-33.5 mg/cm(3), p=0.001), 2-year (258.9+/-32.2 vs. 289.9+/-40.1 mg/cm(3), p=0.003), and 7-year follow-ups (early adulthood, 307.6+/-35.9 vs. 343.6+/-40.9 mg/cm(3), p=0.002). There was a consistent trend towards larger bone cross-sectional area in the fracture cohort compared to non-fracture. In a logistic regression model, lower vBMD (p=0.001) was the only significant predictor of upper-limb fracture during the period of 8-14 years. Our results indicate that low BMD is an important factor underlying elevated upper-limb fracture risk during puberty, and that low BMD in pubertal girls with fracture persists into adulthood. Hence low vBMD during childhood is not a transient deficit. Methods to monitor vBMD and to maximise bone mineral accrual and reduce risks of falling in childhood should be developed.

Trait-specific tracking and determinants of body composition: a 7-year follow-up study of pubertal growth in girls.

BACKGROUND: Understanding how bone (BM), lean (LM) and fat mass (FM) develop through childhood, puberty and adolescence is vital since it holds key information regarding current and future health. Our study aimed to determine how BM, LM and FM track from prepuberty to early adulthood in girls and what factors are associated with intra- and inter-individual variation in these three tissues. METHODS: The study was a 7-year longitudinal cohort study. BM, LM and FM measured using dual-energy X-ray absorptiometry, self-reported dietary information, leisure time physical activity (LTPA) and other factors were assessed one to eight times in 396 girls aged 10 to 13 years (baseline), and in 255 mothers once. RESULTS: The location of a girl's BM, LM and FM in the lower, middle or upper part of the sample distribution was established before puberty and tracked in its percentile of origin over 7 years (r = 0.72 for BM, r = 0.61 for LM, and r = 0.65 for FM all p < 0.001 first vs. last measurements' ranking). Seventy-three percent of those in the lowest quartile for BM and 69% for LM, and 79% of those in the highest quartile for FM at baseline remained in their quartile at 7-year follow-up. Heritability was estimated to contribute 69% of the total variance of the BM, 50% of the LM, and 57% of the FM. Besides body size, diet index (explaining 9% of variance), breast feeding duration (6%) and mother's BM (9%) predicted high BM. Diet index and high LTPA predicted high LM (24% and 14%, respectively), and low FM (25% and 12%, respectively), and low level of parental education predicted high FM (4%). CONCLUSION: Individual levels of BM, LM and FM are established before puberty and track in a trait-specific manner until early adulthood. Girls who are prone to develop low BM and LM and high FM in adulthood can be identified in prepuberty. The developments of three components of body composition are inter-related during growth. BM was the most heritable trait while LM the most environmentally modifiable. Diet and physical activity played an important role in increasing LM and preventing the accumulation of excessive FM.

Assessing body composition with DXA and bioimpedance: effects of obesity, physical activity, and age.

OBJECTIVE: This study evaluated to what extent dual-energy X-ray absorptiometry (DXA) and two types of bioimpedance analysis (BIA) yield similar results for body fat mass (FM) in men and women with different levels of obesity and physical activity (PA). METHODS AND PROCEDURES: The study population consisted of 37-81-year-old Finnish people (82 men and 86 women). FM% was estimated using DXA (GE Lunar Prodigy) and two BIA devices (InBody (720) and Tanita BC 418 MA). Subjects were divided into normal, overweight, and obese groups on the basis of clinical cutoff points of BMI, and into low PA (LPA) and high PA (HPA) groups. Agreement between the devices was calculated by using the Bland-Altman analysis. RESULTS: Compared to DXA, both BIA devices provided on average 2-6% lower values for FM% in normal BMI men, in women in all BMI categories, and in both genders in both HPA and LPA groups. In obese men, the differences were smaller. The two BIA devices provided similar means for groups. Differences between the two BIA devices with increasing FM% were a result of the InBody (720) not including age in their algorithm for estimating body composition. DISCUSSION: BIA methods provided systematically lower values for FM than DXA. However, the differences depend on gender and body weight status pointing out the importance of considering these when identifying people with excess FM.

COL1A1 Sp1 polymorphism associates with bone density in early puberty.

Optimal acquisition of bone mass in puberty is a key determinant of the lifetime risk of osteoporosis and has a strong genetic basis. We investigated the relationship between the COL1A1 Sp1 polymorphism and BMD in early puberty, and how the genotypes relate to bone size and geometry as well as bone turnover and material properties in 247 10- to 13-year-old girls. Bone properties were measured using DXA, pQCT, and ultrasound. Also, serum P1NP, OC, B-ALP, and TRACP 5b were assessed. Our results showed that girls with the TT genotype had significantly lower BMC and BMD of the total body, lumbar spine, and proximal femur, as well as BUA at the calcaneus, than those with the GT and GG genotype. They also had significantly lower B-ALP, as well as P1NP/TRACP 5b and (OC + B-ALP)/TRACP 5b, compared to the others. These findings indicate that the COL1A1 polymorphism is associated with low bone properties in early puberty and suggest a possible physiological effect on collagen metabolism and bone turnover. This information may contribute to the identification of children at risk for suboptimal acquisition of peak bone mass and may ultimately be of value in the planning of early preventive strategies for osteoporosis.

Strategies to improve vitamin D status in northern European children: exploring the merits of vitamin D fortification and supplementation.

Adequacy of vitamin D in children in Europe has been the focus of a number of investigations. The results of measuring serum levels of 25-hydroxyvitamin D show high prevalence of vitamin D deficiency during the winter with lower prevalence during the summer. National policies on food fortification or individual supplementation with vitamin D have been recently revisited by the individual countries and the European Union as a whole. Optiford is a project managed by a coalition of scientists formed to optimize vitamin D fortification in the northern European Countries, was given the task to decide if food fortification with vitamin D is feasible and to provide a scientific basis for setting the vitamin D fortification level in Europe. This article presents the results of these investigations to date, with particular attention to potential corrective strategies to allow children and adolescents living in countries at high latitudes to maintain healthy circulating 25-hydroxyvitamin D levels year around, even in the absence of adequate sun exposure during a significant part of the year.

Effects of calcium, dairy product, and vitamin D supplementation on bone mass accrual and body composition in 10-12-y-old girls: a 2-y randomized trial.

BACKGROUND: Little is known about the relative effectiveness of calcium supplementation from food or pills with or without vitamin D supplementation for bone mass accrual during the rapid growth period. OBJECTIVE: The purpose was to examine the effects of both food-based and pill supplements of calcium and vitamin D on bone mass and body composition in girls aged 10-12 y. DESIGN: This placebo-controlled intervention trial randomly assigned 195 healthy girls at Tanner stage I-II, aged 10-12 y, with dietary calcium intakes <900 mg/d to 1 of 4 groups: calcium (1000 mg) + vitamin D3 (200 IU), calcium (1000 mg), cheese (1000 mg calcium), and placebo. Primary outcomes were bone indexes of the hip, spine, and whole body by dual-energy X-ray absorptiometry and of the radius and tibia by peripheral quantitative computed tomography. RESULTS: With the use of intention-to-treat or efficacy analysis, calcium supplementation with cheese resulted in a higher percentage change in cortical thickness of the tibia than did placebo, calcium, or calcium + vitamin D treatment (P = 0.01, 0.038, and 0.004, respectively) and in higher whole-body bone mineral density than did placebo treatment (P = 0.044) when compliance was >50%. With the use of a hierarchical linear model with random effects to control for growth velocity, these differences disappeared. CONCLUSIONS: Increasing calcium intake by consuming cheese appears to be more beneficial for cortical bone mass accrual than the consumption of tablets containing a similar amount of calcium. Diverse patterns of growth velocity may mask the efficacy of supplementation in a short-term trial of children transiting through puberty.

Vitamin D, parathyroid hormone, and bone mass in adolescents.

This article provides a review of the evidence identifying the factors related to vitamin D status in adolescents. The prevalence of vitamin D deficiency based on 25-hydroxyvitamin D [25(OH)D] of <25 nmol/L ranges from 0 to 32% depending on the season measured and the latitude of the population assessed. The factors that have been reported to affect serum 25(OH)D in adolescents include ethnicity, gender, puberty stage, parathyroid hormone (PTH), dietary vitamin D intake, and sun exposure. Vitamin D supplementation studies are limited to small populations and with supplementation focused on winter months when sunlight may be inadequate. The effects of vitamin D status and supplementation on bone assessment provide varied results. Differences in study design, modalities of bone assessment, and stage of puberty could contribute to disparate findings. Overall, the results from the available literature provide more questions than answers concerning the role of vitamin D in bone accrual in adolescents.

Growth patterns at distal radius and tibial shaft in pubertal girls: a 2-year longitudinal study.

UNLABELLED: Bone changes, in terms of both size and BMD, were assessed longitudinally in pubertal girls. Before puberty, BMD at the distal radius declined, whereas bone size increased, suggesting that normal growing girls experience a transient period of increased bone fragility. This could explain the elevated low-trauma forearm fracture rates reported in earlier studies. INTRODUCTION: Longitudinal data on bone growth during puberty are sparse. Such information is needed to understand the sequence of biological changes, the physical and mechanical consequences for the growing skeleton, and the implications for later life. MATERIALS AND METHODS: The geometric properties and volumetric BMD (vBMD) of the distal radius and tibial shaft were measured using pQCT in 258 pubertal girls followed over 2 years. A new hierarchical linear statistical modeling approach was used to determine true longitudinal trends. RESULTS: The growth rates of cross-sectional area (CSA) and BMC of the distal radius peaked at 16 and 9 months before menarche, respectively. This growth asynchrony between bone size and mass meant that total vBMD of the distal radius declined until 1 year before menarche. At the tibial shaft, total vBMD and cortical vBMD increased monotonically without any such transient reduction. Cortical thickness increased linearly, which was accounted for mainly by bone formation at the periosteal surface before menarche, but by both periosteal and endocortical apposition after menarche. During puberty, the ratio of cortical-to-total CSA of the tibial shaft increased and that of marrow-to-total CSA decreased. CONCLUSIONS: The temporal pattern of bone growth during puberty differs at the distal radius and tibial shaft. A transient decrease in vBMD, arising from asynchronous bone size and mass growth, occurs only at the radius. In the tibia, the mechanism of cortical thickening changes from periosteal apposition premenarche to both periosteal and endocortical apposition postmenarche.

Association between exercise and pubertal BMD is modulated by estrogen receptor alpha genotype.

UNLABELLED: Genetic and environmental factors contribute to bone mass, but the ways they interact remain poorly understood. This study of 245 pre- and early pubertal girls found that the PvuII polymorphism in the ER-alpha gene modulates the effect of exercise on BMD at loaded bone sites. INTRODUCTION: Impaired achievement of bone mass at puberty is an important risk factor for the development of osteoporosis in later life. Genetic, as well as environmental, factors contribute to bone mass, but the ways they interact with each other remain poorly understood. MATERIALS AND METHODS: We investigated the interaction between a PvuII polymorphism at the ER-alpha gene and physical activity (PA) on the modulation of bone mass and geometry in 245 10- to 13-year-old pre- and early pubertal Finnish girls. Level of PA was assessed using a questionnaire. Bone properties were measured using DXA and pQCT. The analyses were controlled for the effects of Tanner stage and body size index. RESULTS: Girls with heterozygote ER-alpha genotype (Pp) and high PA had significantly higher bone mass and BMD, as well as thicker cortex, at loaded bone sites than their low-PA counterparts. No differences were found in bone properties of the distal radius, which is not a weight-bearing bone. Bone properties did not differ in either homozygote groups (PP and pp) regardless of the PA level. CONCLUSIONS: These findings suggest that the PvuII polymorphism in the ER-alpha gene may modulate the effect of exercise on BMD at loaded bone sites. The heterozygotes may benefit most from the effect of exercise, whereas neither of the homozygote groups received any significant improvement from high PA. Furthermore, high PA may hide the genetic influence on bone. Indeed, it seems that one may compensate one's less favorable Pp genotype by increasing leisure PA at early puberty.

Relationship of sex hormones to bone geometric properties and mineral density in early pubertal girls.

This study aimed to evaluate the associations among serum 17beta-estradiol (E2), testosterone (T), sex hormone-binding globulin (SHBG), bone geometric properties, and mineral density in 248 healthy girls between the ages of 10 and 13 yr old. The left tibial shaft was measured by peripheral quantitative computed tomography (Stratec XCT-2000; Stratec Medizintechnik, GmbH, Pforzheim, Germany). The cortical bone and marrow cavity areas were expressed as proportions of the total tibial cross-sectional area (CSA). Cortical thickness and total volumetric bone mineral density (vBMD) were also determined. These tibial geometric and densitometric measures were correlated against the serum sex hormone concentrations after controlling for age and body size. The results showed that E2 was negatively associated with marrow cavity proportion (r = -0.19, P = 0.003) and positively associated with cortical proportion and thickness and with total vBMD (r = 0.26, P < 0.001; r = 0.25, P < 0.001; and r = 0.23, P < 0.001, respectively). However, T was not associated with these bone variables. On the other hand, SHBG was positively associated with marrow cavity proportion (r = 0.17, P = 0.007) and negatively associated with cortical proportion and thickness and with total vBMD (r = -0.14, P = 0.029; r = -0.16, P = 0.010; and r = -0.18, P = 0.005, respectively). Total bone CSA did not correlate with E2, T, or SHBG. These results suggest that E2 has a positive effect on bone geometric and densitometric development by suppressing bone turnover at the endocortical surface during the early pubertal period, that SHBG plays an opposite role to E2, and that T has no detectable effect.

Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early pubertal and prepubertal Finnish girls.

BACKGROUND: Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] and their effects on bone mass in children. OBJECTIVE: We studied the associations of serum 25(OH)D and intact PTH (iPTH) with bone mineral content (BMC) and bone mineral density (BMD) at different bone sites and the relation between serum 25(OH)D and iPTH in early pubertal and prepubertal Finnish girls. DESIGN: The subjects were 10-12-y-old girls (n = 193) at Tanner stage 1 or 2, who reported a mean (+/- SD) dietary calcium intake of 733 +/- 288 mg/d. 25(OH)D, iPTH, tartrate-resistant acid phosphatase 5b (TRAP 5b), urinary calcium excretion, BMC, areal BMD, and volumetric BMD were assessed by using different methods. RESULTS: Thirty-two percent of the girls were vitamin D deficient [serum 25(OH)D < or = 25 nmol/L], and 46% of the girls had an insufficient concentration (26-40 nmol/L). iPTH and TRAP 5b concentrations were significantly higher in the deficient group than in the insufficient and sufficient groups [iPTH: 43.9 +/- 15.7 compared with 38.6 +/- 11.2 pg/L (P = 0.049) and 32.7 +/- 12.1 pg/L (P < 0.001), respectively; TRAP 5b: 12.2 +/- 2.9 compared with 11.0 +/- 2.8 U/L (P = 0.009) and 10.9 +/- 1.9 U/L (P = 0.006), respectively]. The girls in the deficient group also had significantly lower cortical volumetric BMD of the distal radius (P < 0.001) and tibia shaft (P = 0.002). High iPTH concentrations were also associated with low total-body apparent mineral density and urinary calcium excretion (P < 0.007). CONCLUSIONS: Vitamin D-deficient girls have low cortical BMD and high iPTH concentrations, which are consistent with secondary hyperparathyroidism. A low vitamin D concentration accompanied by high bone resorption (TRAP 5b) may limit the accretion of bone mass in young girls.