Arja Lyytikäinen

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).

Growth Patterns at Distal Radius and Tibial Shaft in Pubertal Girls: A 2-Year Longitudinal Study†

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.

Association Between Exercise and Pubertal BMD Is Modulated by Estrogen Receptor α Genotype

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‐α gene modulates the effect of exercise on BMD at loaded bone sites.

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.

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.

Food consumption and nutrient intakes with a special focus on milk product consumption in early pubertal girls in Central Finland

OBJECTIVE To evaluate the current status of dietary intakes in early pubertal girls with a special focus on milk products. DESIGN Cross-sectional data using 3-day food records. SUBJECTS Eight hundred and sixty girls, aged 10-12 years, at Tanner maturation stage I-III. RESULTS The mean consumption of milk products (620 g day(-1)) was similar to that of a Finnish study in the 1980s, while the consumption of non-milk drinks (403 g day(-1)) had increased. Twelve per cent of the girls had a dairy-restricted diet and consumed significantly less milk products than girls with a non-restricted diet (465 vs. 644 g day(-1), P<0.001). Girls with low milk product consumption had the highest non-milk drinks consumption (P<0.001). The mean energy intake was 7.1 MJ day(-1). No major changes were found in the sources of nutrients. The shares of energy for nutrients were close to recommendations except for saturated fat (13.9 vs. 10% of energy) and carbohydrates (51.5 vs. 55-60% of energy). The mean calcium intake (1117 mg day(-1)) was above the recommendation, while the vitamin D intake (3.1 microg day(-1)) of 88% of the girls was below the recommendation. CONCLUSIONS The diet quality of early pubertal girls is close to the recommendations and has improved with respect to fat compared with the 1980s. Consumption of milk products is high although the consumption of non-milk drinks has increased. We found a subgroup of girls who compensate their low milk product consumption with a higher consumption of non-milk drinks. Following a dairy-restricted diet is the main reason for low consumption of milk products.

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 (E2), 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, E2, and T were determined. Musculoskeletal properties in the left lower leg were measured using peripheral quantitative computed tomography (pQCT). Serum levels of IGF‐1, E2, 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. E2 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.

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 (L2–L4) 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 (GLL), consistently high (GHH), and changed from low to high (GLH) and from high to low (GHL) 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 GLL group, the GHH 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 GLH 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 GLL (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.

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.