Association Between Health-Related Quality of Life, Obesity, Fitness, and Sleep Quality in Young Adults: The Cuenca Adult Study.

OBJECTIVE: The objectives of this study were to examine in university students: (a) the mean differences in the HRQoL among fat mass percentage, cardiorespiratory fitness (CRF) and sleep quality categories; and (b) the independent associations among fat mass percentage, CRF, and sleep quality with HRQoL. PARTICIPANTS: 376 students, 18-30 years old, from the University of Castilla-La Mancha in Cuenca, Spain (during 2009-2010). METHOD: Cross-sectional study measuring % fat mass (DXA), CRF (20-m shuttle run test), sleep quality (Pittsburgh Sleep Quality Index), and HRQoL (SF-12 questionnaire). RESULTS: The mean in Mental Component Summary (MCS) in men (p = .029) was lower in students in upper quartiles of % fat mass than in peers in other categories of % fat mass. Among men, MCS was significantly lower among those in the lowest quartile of CRF (p = .015), and among women, Physical Component Summary (PCS) was significantly lower among those in the lowest quartile of CRF (p = .047). MCS dimension of the HRQoL was lower in both men (p = .001) and women (p < .001) in upper quartiles of sleep quality. Multiple linear regression models showed that in men, CRF was associated with MCS (ß = 0.25, p = .031), and sleep quality was associated with PCS (ß = -0.24, p = .027) and MCS (ß = -0.38, p < .001). In women, CRF was associated with PCS (ß = 0.17, p = .018) and sleep quality with MCS (ß= -0.44, p < .001). CONCLUSIONS: Finally, our findings suggest that, regardless of adiposity and fitness, having good sleep habits may positively influence the quality of life in young adults.

Relationship between cardiorespiratory fitness and blood pressure in young adults: a mediation analysis of body composition.

High blood pressure levels are among the most important cardiovascular disease risk factors and are influenced by physical fitness and body composition. However, the degree to which obesity may attenuate or modify the beneficial effects of physical fitness on blood pressure levels in young adults is uncertain. Thus, the aim of this study was to analyze whether body composition is a mediator between cardiorespiratory fitness (CRF) and blood pressure levels in young adults. This work was a cross-sectional study involving first-year college students (n=386) at the University Campus of Cuenca (Spain). We measured weight, height, waist circumference, fat mass percentage (by densitometry), systolic and diastolic blood pressure and CRF levels (by a 20 m shuttle run test). Partial correlation coefficients were estimated to examine the relationships among adiposity variables, CRF and blood pressure variables, controlling for age and sex. ANCOVA models were conducted to explore differences in blood pressure levels across adiposity and CRF categories. Hayes's PROCESS macro was used for the simple mediation analysis. The indirect effect and Sobel test were significant (P<0.001), confirming that all body composition variables mediate between CRF and all of the included blood pressure variables. All body composition variables acted as mediators between CRF and blood pressure. These results highlight the importance of maintaining a healthy body composition to prevent hypertension in young adults.

Insulin and bone health in young adults: The mediator role of lean mass.

BACKGROUND: The positive relationship between lean mass (LM) and bone health is well known, but a positive association between insulin and LM has also been described. Insulin has some anabolic properties on bone through the stimulation of osteoblast differentiation, yet the role of LM as a confounder or mediator in this relationship remains uncertain. OBJECTIVE: To examine whether the association between insulin levels and bone health is mediated by LM. METHODS: A cross-sectional study was conducted at the Castilla La Mancha University (Spain) involving 466 young adults (113 young men; 19.5±2.3 years). LM and total-body bone mineral content (BMC) were measured by dual energy x-ray absorptiometry, and insulin was measured in fasting serum samples. RESULTS: Young adults with high total LM had higher values of total-body BMC than their peers after controlling for age and sex, this relationship persisted after adjusting for insulin levels (p<0.001). In mediation analyses, insulin levels were positively associated with total-body BMC (b = 0.05; p<0.001) and total LM acted as an intermediate variable, attenuating the association between insulin levels and total-body BMC (b = -31.98; p>0.05) as indicated by Sobel test values for indirect effect (z = 4.43; p<0.001). CONCLUSIONS: LM plays an important role in the relationship between insulin levels and bone health, in such a way that while increases in LM have a positive influence on bone health, they are also negatively associated with insulin levels.

[Relationship between weight status, physical fitness levels and blood pressure components in young women]. / Relación entre estatus ponderal, nivel de condición física y componentes de la presión arterial en mujeres de entre 18 y 30 años de edad.

BACKGROUND: As far as we know there are not studies that analyze jointly the relationship between obesity, cardiorespiratory fitness and muscle strength with blood pressure (BP).We aimed to determine the relationship between BMI and physical fitness with components of BP in young women. METHODS: cross-sectional study in 407 women aged 18-to-30 years. VARIABLES: weight, height, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP: DBP+[0,333× (SBP-DBP)]) and pulse pressure (PP: SBP-DBP), and physical fitness (cardiorespiratory fitness and muscle strength). RESULTS: Mean age of participants was 20.1 ± 4.4 years. Mean SBP, DBP, MAP and PP were respectively: women with normal weight 108,0 ± 8.9, 67.7 ± 6.7, 81.1 ± 6.8 and 40.3 ± 6, 6 mmHg; in obese women 123.1 ± 8.9, 80.5 ± 6.2, 94.7 ± 6.5 and 42.5 ± 6.2 mmHg; in those with low aerobic capacity 110.9 ± 9.9, 70.5 ± 7.6, 84.0 ± 7.7 and 40.3 ± 7.3 mmHg, and in those with high aerobic capacity 107.4 ± 9.3, 67.0 ± 7.0, 80.4 ± 7.2 and 40.4 ± 6.6 mmHg. Muscle strength was not statistically associated with any of the components of PA (p> 0.05). In multiple linear regression models of SBP was associated with BMI and muscle strength index (p = ≤ 0.05), DBP and MAP with BMI, index of muscle strength and aerobic capacity (p = ≤ 0.05), and PP with BMI (p = <0.05). CONCLUSIONS: In young women BMI and muscle strength have a direct relationship with BP, and cardiorespiratory fitness an inverse relationship; however the latter is not associated with SBP and PP.