Tuija M. Mikkola

association Between Physical Performance and Sense of Autonomy in Outdoor Activities and Life-space Mobility in Community-dwelling Older People

To study the relationship between physical performance and sense of autonomy in outdoor activities with life‐space mobility—the spatial area a person purposefully moves through in daily life—in community‐dwelling older people.

Serum Osteocalcin Is Not Associated with Glucose but Is Inversely Associated with Leptin across Generations of Nondiabetic Women

CONTEXT The skeleton is recognized as an important player in energy metabolism through its interactions with other tissues. Whether the association of osteocalcin with glucose metabolism is age dependent has not been fully addressed. OBJECTIVE The objective of the study was to examine the age-specific association between different forms of osteocalcin and glucose and adipokines. DESIGN This was a family-based study across three generations. SETTING The study was conducted at a university laboratory. PARTICIPANTS Sixty-four daughter-premenopausal mother-maternal grandmother trios participated in the study. METHODS Fasting plasma glucose and insulin concentrations, serum total (tOC), carboxylated (cOC), and uncarboxylated (ucOC = tOC - cOC) osteocalcin, leptin, and adiponectin levels, and fat masses were assessed. Generalized estimating equations (GEE) model was used to assess the associations of bone biomarkers with glucose metabolism variables and adipokines. RESULTS No significant difference in insulin was found between generations, whereas glucose and leptin increased with age. Levels of tOC, cOC, and ucOC were highest in girls and lowest in mothers (P < 0.01). Grandmothers had higher leptin and adiponectin than mothers and girls. Despite the differences in insulin and glucose between the low and high homeostasis model assessment insulin resistance index (HOMA-IR) groups within generations, no significant differences in tOC, cOC, and ucOC were found. Compared with their low HOMA-IR counterparts, the high HOMA-IR group had significantly higher leptin and lower adiponectin in mothers and grandmothers. The tOC, cOC, and ucOC levels did not correlate with HOMA-IR, leptin, or adiponectin when the three generations were evaluated together, but when separated by generation, leptin was inversely correlated with tOC (P = 0.003) and cOC (P = 0.047) in mothers and with ucOC in grandmothers (P = 0.042). CONCLUSIONS Osteocalcin, glucose, and adipokines change with age but in a noncommensurate manner. We infer that the association between osteocalcin and glucose metabolism is minor and age specific in nondiabetic women. Leptin, however, strongly correlated with insulin resistance independently of fat masses, suggesting that obesity, as a metabolic disorder risk factor, affects glucose metabolism, partly through the role of leptin.

Genetic and environmental influence on structural strength of weight-bearing and non-weight-bearing bone: a twin study.

A bivariate genetic analysis among 217 older female twin pairs showed that, although the structural strength of tibia and radius are mainly regulated by same genetic and environmental factors, the tibia is more affected by environment.

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.

Muscle Cross-Sectional Area and Structural Bone Strength Share Genetic and Environmental Effects in Older Women

The purpose of this study was to estimate to what extent muscle cross‐sectional area of the lower leg (mCSA) and tibial structural strength are influenced by common and trait‐specific genetic and environmental factors. pQCT scans were obtained from both members of 102 monozygotic (MZ) and 113 dizygotic (DZ) 63‐ to 76‐yr‐old female twin pairs to estimate the mCSA of the lower leg, structural bending strength of the tibial shaft (BSIbend), and compressive strength of the distal tibia (BSIcomp). Quantitative genetic models were used to decompose the phenotypic variances into common and trait‐specific additive genetic (A), shared environmental (C), and individual environmental (E) effects. The age‐adjusted trivariate independent pathway model showed that the total relative contributions of A, C, and E were, respectively, 75%, 0%, and 25% for mCSA, 55%, 20%, and 25% for BSIbend, and 40%, 37%, and 23% for BSIcomp. In addition, the model showed that all three traits shared genetic and individual environmental factors. BSIbend and BSIcomp had common shared environmental factors and were also influenced by trait‐specific genetic factors. In conclusion, the association between muscle cross‐sectional area and structural bone strength has its origins in both genetic and environmental effects in older women. These results suggest that in older women the same genetic and environmental factors may predispose to or, conversely, protect from both sarcopenia and bone fragility.

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.

Life-space mobility and dimensions of depressive symptoms among community-dwelling older adults

Objectives: To examine the association between life-space mobility and different dimensions of depressive symptoms among older community-dwelling people. Methods: Cross-sectional analyses of baseline data of the ‘Life-Space Mobility in Old Age’ cohort study were carried out. The participants were community-dwelling women and men aged 75–90 years (N = 848). Data were gathered via structured interviews in participants’ home. Life-space mobility (the University of Alabama at Birmingham (UAB) Life-Space Assessment – questionnaire) and depressive symptoms (Centre for Epidemiological Studies Depression Scale, CES-D) were assessed. Other factors examined included sociodemographic factors, difficulties walking 500 m, number of chronic diseases and the sense of autonomy in participation outdoors (subscale of Impact on Participation and Autonomy questionnaire). Results: Poorer life-space mobility was associated with higher prevalence of different dimensions of depressive symptoms. The associations were partially mediated through walking difficulties, health and the sense of autonomy in participation outdoor activities. Conclusion: Poorer life-space mobility interrelates with higher probability for depressive symptoms, thus compromising older adults’ mental wellbeing. A focus on older adults’ life-space mobility may assist early identification of persons, who have elevated risk for depressive symptoms. The association between life-space mobility and depressive symptoms should be studied further utilizing longitudinal study designs to examine temporality and potential causality.

Association of Self-Reported Hearing Difficulty to Objective and Perceived Participation Outside the Home in Older Community-Dwelling Adults

Objective: To investigate whether hearing difficulty is associated with objective and perceived participation in social and leisure activities outside the home in older adults. Method: Self-reported hearing difficulty, frequency of participation, perceived participation and Mini-Mental State Examination (MMSE) were obtained from 848 community-dwelling men and women aged 75 to 90. Results: Among persons with MMSE ≤ 24, hearing was not associated with participation. In persons with MMSE > 24, relative to persons who reported no difficulty hearing, participants with major hearing difficulty had a higher odds ratio [OR] for infrequent participation in group activities (OR 2.1, 95% confidence interval [CI] [1.2, 3.6]) and more restricted perceived participation (OR 2.1, 95% CI [1.2, 3.7]). Participants with and without hearing difficulty did not differ in their frequency of attending non-group activities or meeting (grand)children or acquaintances. Discussion: Hearing difficulty may restrict older adults with normal cognition from participating in social and leisure activities and living their life as they would like to outside the home.

Self-Reported Hearing Status Is Associated with Lower Limb Physical Performance, Perceived Mobility, and Activities of Daily Living in Older Community-Dwelling Men and Women

To explore the associations between self‐reported hearing problems and physical performance and self‐reported difficulties in mobility and activities of daily living (ADLs) in community‐dwelling older adults.

Effects of exercise and diet interventions on obesity-related sleep disorders in men: study protocol for a randomized controlled trial

BackgroundSleep is essential for normal and healthy living. Lack of good quality sleep affects physical, mental and emotional functions. Currently, the treatments of obesity-related sleep disorders focus more on suppressing sleep-related symptoms pharmaceutically and are often accompanied by side effects. Thus, there is urgent need for alternative ways to combat chronic sleep disorders. This study will investigate underlying mechanisms of the effects of exercise and diet intervention on obesity-related sleep disorders, the role of gut microbiota in relation to poor quality of sleep and day-time sleepiness, as well as the levels of hormones responsible for sleep-wake cycle regulation.Methods/designParticipants consist of 330 (target sample) Finnish men aged 30 to 65 years. Among them, we attempt to randomize 180 (target sample) with sleep disorders into exercise and diet intervention. After screening and physician examination, 101 men with sleep disorders are included and are randomly assigned into three groups: exercise (n = 33), diet (n = 35), and control (n = 33). In addition, we attempt to recruit a target number of 150 healthy men without sleep disorders as the reference group. The exercise group undergoes a six-month individualized progressive aerobic exercise program based on initial fitness level. The diet group follows a six month specific individualized diet program. The control group and reference group are asked to maintain their normal activity and diet during intervention. Measurements are taken before and after the intervention. Primary outcomes include objective sleep measurements by polysomnography and a home-based non-contact sleep monitoring system, and subjective sleep evaluation by questionnaires. Secondary outcome measures include anthropometry, body composition, fitness, sleep disorder-related lifestyle risk factors, composition of gut microbiota and adipose tissue metabolism, as well as specific hormone and neurotranmitter levels and inflammatory biomarkers from venous blood samples.DiscussionIt is expected that the improvement of sleep quality after exercise and diet intervention will be evident both in subjective and objective measures of quality of sleep. Additionally, the change of sleep quality induced by exercise and diet intervention is expected to be related to the changes in specific hormones and inflammatory biomarkers, and in the composition of gut microbiota.Trial registrationCurrent Controlled Trials ISRCTN77172005