Aerobic capacity in adolescence is associated with time to intervention in adult men with atrial septal defects.

BACKGROUND: Atrial septal defect (ASD) is a congenital heart lesion that often remains undiagnosed until adulthood. The reasons for this may be multifactorial. It is, however, known that closure of a hemodynamically significant ASD improves exercise capacity. This study aimed to explore whether the aerobic capacity in late adolescence is associated with time to diagnosis and intervention in adult men with late diagnosis of an atrial shunt. METHODS: The Swedish Military Conscription Service Register contains data on exercise tests performed in late adolescence. By linking these data with the National Patient Register, 254 men with a later intervention for an ASD were identified. RESULTS: Interventions were performed at a mean of 26.5 ±â€¯7.9 years after the initial exercise tests. The mean absolute workload among those with a later diagnosed ASD was similar to those without a later diagnosed ASD (274 ±â€¯51 W vs. 276 ±â€¯52 W, p = 0.49). Men with a higher exercise capacity (≥1 SD) had their intervention earlier (21.9 ±â€¯8.6 years vs. 27.5 ±â€¯7.4 years, p < 0.001). CONCLUSIONS: The aerobic exercise capacity was similar in adolescent men with later interventions for ASD compared to the reference population. Furthermore, those with high exercise capacity appeared to be diagnosed earlier. Thus, low exercise capacity may not be a feature of ASD during adolescence, but rather develop later in life as a natural progression of the disease.

Aerobic fitness in late adolescence and the risk of early death: a prospective cohort study of 1.3 million Swedish men.

BACKGROUND: Fitness level and obesity have been associated with death in older populations. We investigated the relationship between aerobic fitness in late adolescence and early death, and whether a high fitness level can compensate the risk of being obese. METHODS: The cohort comprised 1 317 713 Swedish men (mean age, 18 years) that conscripted between 1969 and 1996. Aerobic fitness was assessed by an electrically braked cycle test. All-cause and specific causes of death were tracked using national registers. Multivariable adjusted associations were tested using Cox regression models. RESULTS: During a mean follow-up period of 29 years, 44 301 subjects died. Individuals in the highest fifth of aerobic fitness were at lower risk of death from any cause [hazard ratio (HR), 0.49; 95% confidence interval (CI), 0.47-0.51] in comparison with individuals in the lowest fifth, with the strongest association seen for death related to alcohol and narcotics abuse (HR, 0.20; 95% CI, 0.15-0.26). Similar risks were found for weight-adjusted aerobic fitness. Aerobic fitness was associated with a reduced risk of death from any cause in normal-weight and overweight individuals, whereas the benefits were reduced in obese individuals (P < 0.001 for interaction). Furthermore, unfit normal-weight individuals had 30% lower risk of death from any cause (HR, 0.70; 95% CI, 0.53-0.92) than did fit obese individuals. CONCLUSIONS: Low aerobic fitness in late adolescence is associated with an increased risk of early death. Furthermore, the risk of early death was higher in fit obese individuals than in unfit normal-weight individuals.

Risk factors assessed in adolescence and the later risk of stroke in men: a 33-year follow-up study.

BACKGROUND: Stroke is a common cause of death, and a leading contributor to long-term disability. The cost associated with the disease is great. Several modifiable risk factors for stroke have been found in older cohorts; however, no study to date has investigated the effects of these risk factors from late adolescence. METHODS: The study cohort comprised 811,579 Swedish men (mean age, 18 years) that participated in the mandatory military conscription service in Sweden between 1969 and 1986. Some risk factors for stroke, such as body mass index, systolic and diastolic blood pressure, and cognitive function, were assessed at conscription. Aerobic fitness was also assessed at conscription, using a braked ergometer cycle test. Other risk factors for stroke, including stroke in subjects' parents, and socioeconomic factors including highest achieved level of education and annual income 15 years after conscription, were collected through national register linkage using the personal identification number. Stroke diagnosis among the study participants was tracked in the National Hospital Discharge Patient Register. RESULTS: During a median follow-up period of 33 years 6,180 ischemic strokes and 2,104 hemorrhagic strokes were diagnosed in the cohort at a mean age of 47.9 years. Strong independent risk factors (all p <1.0 × 10-(6)) for ischemic stroke included low aerobic fitness (hazard ratio [HR], 0.84 per standard deviation [SD] increase), high BMI (HR, 1.15 per SD increase), diabetes (HR, 2.85), alcohol intoxication (HR, 1.93), low annual income (HR, 0.85 per SD decrease), and stroke in the mother (HR, 1.31). Similar risk factors were found for hemorrhagic stroke including low aerobic fitness (HR, 0.82 per SD increase), high BMI (HR, 1.18 per SD increase) alcohol intoxication (HR, 2.92), diabetes (HR, 2.06), and low annual income (HR, 0.75). The population attributable risks associated with all evaluated risk factors were 69% for ischemic stroke and 88% for hemorrhagic stroke (p < 0.001 for both). CONCLUSIONS: In the present study we have shown that several known risk factors for stroke are present already in late adolescence, and that they are independent of each other. The strongest risk factors were low physical fitness, high BMI, diabetes, low annual income and a maternal history of stroke. Several of the aforementioned risk factors are potentially modifiable.

High aerobic fitness in late adolescence is associated with a reduced risk of myocardial infarction later in life: a nationwide cohort study in men.

AIMS: Cardiovascular disease is the leading cause of morbidity and mortality worldwide, and signs of atherosclerosis are present in all large arteries already in adolescence. We investigated the association between high physical fitness in late adolescence and myocardial infarction (MI) later in life. METHODS AND RESULTS: The study cohort comprised 743 498 Swedish men examined at the age of 18 years during conscription 1969-84. Aerobic fitness (Wmax) and muscle strength at conscription were measured using standardized methods. Myocardial infarctions occurring in the cohort were tracked through national registers. During a median follow-up period of 34 years, 11 526 MIs were registered in the cohort. After adjusting for age, body mass index (BMI), diseases, education, blood pressure, and socio-economic factors, one standard deviation increase in the level of physical fitness (Wmax) was associated with an 18% decreased risk of later MI [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.80-0.85]. The beneficial effects of Wmax were significant across all recognized BMI groups, ranging from lean (BMI < 18.5) to obese (BMI > 30) (P < 0.05 for all). However, obese men (BMI > 30) in the highest fourth of Wmax had a higher risk of MI than did lean men (BMI < 18.5) in the highest (HR 4.6, 95% CI 1.9-11.2), and lowest (HR 1.7, 95% CI 1.2-2.6) fourth of Wmax. CONCLUSIONS: We report a significant graded association between aerobic fitness in late adolescence and MI later in life in men. However, obese men with a high aerobic fitness had a higher risk of MI than lean men with a low aerobic fitness.

Body composition and performance: influence of sport and gender among adolescents.

Body composition is well known to be associated with endurance performance among adult skiers; however, the association among adolescent crosscountry and alpine skiers is inadequately explored. The study sample comprised 145 male and female adolescent subjects (aged 15-17 years), including 48 crosscountry skiers, 33 alpine skiers, and 68 control subjects. Body composition (%body fat [BF], %lean mass [LM], bone mineral density [grams per centimeter squared]) was measured with a dual-emission x-ray absorptiometer, and pulse and oxygen uptake was measured at 3 break points during incremental performance tests to determine physical fitness levels. Female crosscountry and alpine skiers were found to have significantly higher %LM (mean difference = 7.7%, p < 0.001) and lower %BF (mean difference = 8.1%, p < 0.001) than did female control subjects. Male crosscountry skiers were found to have lower %BF (mean difference = 3.2%, p < 0.05) and higher %LM (mean difference = 3.3%, p < 0.01) than did male alpine skiers and higher %LM (mean difference = 3.7%, p < 0.05) and %BF (mean difference = 3.2%, p < 0.05) than did controls. This study found strong associations between %LM and the onset of blood lactate accumulation and VO2max weight adjusted thresholds among both genders of the crosscountry skiing cohort (r = 0.47-0.67, p < 0.05) and the female alpine-skiing cohort (r = 0.77-0.79, p < 0.001 for all). This study suggests that body composition is associated with physical performance amongst adolescents.

Higher muscle mass but lower gynoid fat mass in athletes using anabolic androgenic steroids.

This study evaluated the relationship between anabolic androgenic steroid (AAS) use and body constitution. Dual-energy x-ray absorptiometry was used to measure bone mineral density (BMD, g·cm(-2)) of the total body, arms, and legs. Total gynoid and android fat mass (grams) and total lean mass (grams) were measured in 10 strength trained athletes (41.4 ± 7.9 years) who had used AASs for 5-15 years (Doped) and 7 strength trained athletes (29.4 ± 6.2 years) who had never used AASs (Clean). Seventeen sedentary men (30.3 ± 2.1 years) served as Controls. Doped athletes had significantly more lean body mass (85.5 ± 3.8 vs. 75.3 ± 2.5 vs. 60.7 ± 1.9, p < 0.001) and a greater index of fat-free/fat mass (5.8 vs. 2.6 vs. 2.5, p < 0.001) compared with Clean athletes and Controls. Doped athletes also had significantly less gynoid fat mass compared with that of Clean athletes (2.8 ± 0.4 vs. 4.8 ± 0.2 kg, p = 0.02). There were no differences in BMD between the athletes (p = 0.39-0.98), but both groups had significantly higher BMDs at all sites compared with that of Controls (p = 0.01 to <0.001). Thus, long-term AAS use seems to alter body constitution, favoring higher muscle mass and reduced gynoid fat mass without affecting BMD.