Arterial stiffness but not carotid intima-media thickness progression precedes premature structural and functional cardiac damage in youth: A 7-year temporal and mediation longitudinal study

Differences between brachial and aortic blood pressure in adolescence and their implications for diagnosis of hypertension

OBJECTIVES

Blood pressure (BP) is the leading global cause of mortality, and its prevalence is increasing in children and adolescents. Aortic BP is lower than brachial BP in adults. We aimed to assess the extent of this difference and its impact on the diagnosis of hypertension among adolescents.

METHODS

We used data from 3850 participants from a UK cohort of births in the early 1990s in the Southwest of England, who attended their ∼17-year follow-up and had valid measures of brachial and aortic BP at that clinic [mean (SD) age 17.8 (0.4) years, 66% female individuals]. Data are presented as mean differences [95% prediction intervals] for both sexes.

RESULTS

Aortic systolic BP (SBP) was lower than brachial SBP [male, -22.3 (-31.2, -13.3) mmHg; female, -17.8 (-25.5, -10.0) mmHg]. Differences between aortic and brachial diastolic BP (DBP) were minimal. Based on brachial BP measurements, 101 male individuals (6%) and 22 female individuals (1%) were classified as hypertensive. In contrast, only nine male individuals (<1%) and 14 female individuals (<1%) met the criteria for hypertension based on aortic BP, and the predictive value of brachial BP for aortic hypertension was poor (positive-predictive value = 13.8%). Participants with aortic hypertension had a higher left ventricular mass index than those with brachial hypertension.

CONCLUSION

Brachial BP substantially overestimates aortic BP in adolescents because of marked aortic-to-brachial pulse pressure amplification. The use of brachial BP measurement may result in an overdiagnosis of hypertension during screening in adolescence.

Association of Aortic Stiffness and Pressure Pulsatility With Noninvasive Estimates of Hepatic Steatosis and Fibrosis: The Framingham Heart Study

BACKGROUND

Arterial stiffening may contribute to the pathogenesis of metabolic dysfunction-associated steatotic liver disease. We aimed to assess relations of vascular hemodynamic measures with measures of hepatic steatosis and fibrosis in the community.

METHODS

Our sample was drawn from the Framingham Offspring, New Offspring Spouse, Third Generation, Omni-1, and Omni-2 cohorts (N=3875; mean age, 56 years; 54% women). We used vibration-controlled transient elastography to assess controlled attenuation parameter and liver stiffness measurements as measures of liver steatosis and liver fibrosis, respectively. We assessed noninvasive vascular hemodynamics using arterial tonometry. We assessed cross-sectional relations of vascular hemodynamic measures with continuous and dichotomous measures of hepatic steatosis and fibrosis using multivariable linear and logistic regression.

RESULTS

In multivariable models adjusting for cardiometabolic risk factors, higher carotid-femoral pulse wave velocity (estimated β per SD, 0.05 [95% CI, 0.01-0.09]; P=0.003), but not forward pressure wave amplitude and central pulse pressure, was associated with more liver steatosis (higher controlled attenuation parameter). Additionally, higher carotid-femoral pulse wave velocity (β=0.11 [95% CI, 0.07-0.15]; P<0.001), forward pressure wave amplitude (β=0.05 [95% CI, 0.01-0.09]; P=0.01), and central pulse pressure (β=0.05 [95% CI, 0.01-0.09]; P=0.01) were associated with more hepatic fibrosis (higher liver stiffness measurement). Associations were more prominent among men and among participants with obesity, diabetes, and metabolic syndrome (interaction P values, <0.001-0.04). Higher carotid-femoral pulse wave velocity, but not forward pressure wave amplitude and central pulse pressure, was associated with higher odds of hepatic steatosis (odds ratio, 1.16 [95% CI, 1.02-1.31]; P=0.02) and fibrosis (odds ratio, 1.40 [95% CI, 1.19-1.64]; P<0.001).

CONCLUSIONS

Elevated aortic stiffness and pressure pulsatility may contribute to hepatic steatosis and fibrosis.

Associations of Sedentary Time and Physical Activity From Childhood With Lipids: A 13-Year Mediation and Temporal Study

CONTEXT

Among children, evidence on long-term longitudinal associations of accelerometer-measured sedentary time, light physical activity (LPA), and moderate to vigorous PA (MVPA) with lipid indices are few. The mediating role of body composition and other metabolic indices in these associations remains unclear and whether poor movement behavior precedes altered lipid levels is unknown.

OBJECTIVE

This study examined the associations of sedentary time, LPA, and MVPA from childhood through young adulthood with increased lipids, the mediating role of body composition, and whether temporal interrelations exist.

METHODS

Data from 792 children (58% female; mean [SD] age at baseline, 11.7 [0.2] years), drawn from the Avon Longitudinal Study of Parents and Children (ALSPAC) UK birth cohort, who had at least 2 time-point measures of accelerometer-based sedentary time, LPA, and MVPA during clinic visits at ages 11, 15, and 24 years and complete fasting plasma high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, and total cholesterol measured during follow-up visits at ages 15, 17, and 24 years were analyzed.

RESULTS

Total fat mass partly mediated the inverse associations of LPA with low-density lipoprotein cholesterol by 13%, triglyceride by 28%, and total cholesterol by 6%. Total fat mass mediated the inverse associations of MVPA with low-density lipoprotein cholesterol by 37% and total cholesterol by 48%, attenuating the effect on total cholesterol to nonsignificance (P = .077). In the temporal path analyses, higher MVPA at age 15 years was associated with lower low-density lipoprotein cholesterol at 24 years (β = -0.08, SE, 0.01, P = .022) but not vice versa.

CONCLUSION

Sedentary time worsens lipid indices, but increased LPA had a 5- to 8-fold total cholesterol-lowering effect and was more resistant to the attenuating effect of fat mass than MVPA.

Abnormal vascular thickness and stiffness in young adults with type 1 diabetes: new insights from cutting-edge ultrasound modalities

BACKGROUND

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in patients with Type 1 Diabetes (T1D). Early markers of CVD include increased carotid intima-media thickness (CIMT) and pulse wave velocity (PWV), but these existing ultrasound technologies show limited spatial and temporal resolution in young adults. The purpose of this study is to evaluate the utility of high-resolution ultrasound modalities, including high frequency ultrasound CIMT (hfCIMT) and ultrafast ultrasound PWV (ufPWV), in young adults with Type 1 Diabetes.

METHODS

This is a prospective single-center observational cohort study including 39 participants with T1D and 25 age and sex matched controls. All participants underwent hfCIMT and ufPWV measurements. hfCIMT and ufPWV measures of T1D were compared with controls and associations with age, sex, BMI, A1c, blood pressure, and lipids were studied.

RESULTS

Mean age was 24.1 years old in both groups. T1D had a greater body mass index (27.7 [5.7] vs 23.1 [3.2] kg/m2), LDL Cholesterol, and estimated GFR, and had a mean A1c of 7.4 [1.0] % (57 mmol/mol) and diabetes duration of 16.1 [3.7] years with 56% using insulin pumps. In T1D, hfCIMT was significantly increased as compared to controls (0.435 ± 0.06 mm vs 0.379 ± 0.06 mm respectively, p < 0.01). ufPWV measures were significantly increased in T1D (systolic foot PWV: 5.29 ± 0.23 m/s vs 5.50 ± 0.37 m/s, p < 0.01; dicrotic notch PWV = 7.54 ± 0.46 m/s vs 7.92 ± 0.41 m/s, p < 0.01). Further, there was an impact of A1c-measured glycemia on hfCIMT, but this relationship was not seen with ufPWV. No significant statistical correlations between hfCIMT and ufPWV measures in either T1D or healthy controls were observed.

CONCLUSION

Young adults with T1D present with differences in arterial thickness and stiffness when compared with controls. Use of novel high-resolution ultrasound measures describe important relationships between early structural and vascular pathophysiologic changes and are promising tools to evaluate pre-clinical CVD risk in youth with T1D.

TRIAL REGISTRATION

ISRCTN91419926.

Accelerometer-based sedentary time and physical activity from childhood through young adulthood with progressive cardiac changes: a 13-year longitudinal study

AIMS

Longitudinal evidence on the relationship of sedentary time (ST), light-intensity physical activity (LPA), and moderate-to-vigorous-intensity physical activity (MVPA) with changes in cardiac structure and function in the paediatric population is scarce. This evidence is clinically important due to the impact ST can have on the long-term prognosis of healthy young population in the lifetime continuum. This prospective observational study examined the relationships of cumulative ST, LPA, and MVPA from childhood with longitudinal changes in cardiac structure and function.

METHODS AND RESULTS

This is a secondary analysis from the Avon Longitudinal Study of Parents and Children, UK birth cohort of 1682 children aged 11 years. Participants who had at least one follow-up timepoints accelerometer-measured ST, LPA, and MVPA over a period of 13 years and repeated echocardiography-measured cardiac structure and function at ages 17- and 24-year clinic visit were included. Left ventricular mass indexed for height2.7 (LVMI2.7) and left ventricular (LV) diastolic function from mitral E/A ratio (LVDF) were computed. Among 1682 children (mean [SD] age, 11.75 [0.24] years; 1054 [62.7%] females), the cumulative one-min/day increase in ST from ages 11 to 24 years was associated with progressively increased LVMI2.7 {effect estimate 0.002 g/m2.7 [confidence interval (CI) 0.001-0.003], P < 0.001}, irrespective of sex, obesity, and hypertensive status. Cumulative one-min/day increase in LPA was associated with a decreased LVMI2.7 (-0.005 g/m2.7 [-0.006 to -0.003], P < 0.0001) but an increased LVDF. Cumulative one-minute/day increase in MVPA was associated with progressively increased LVMI2.7 (0.003 g/m2.7 [0.001-0.006], P = 0.015).

CONCLUSION

ST contributed +40% to the 7-year increase in cardiac mass, MVPA increased cardiac mass by +5%, but LPA reduced cardiac mass by -49%. Increased ST may have long-term pathologic effects on cardiac structure and function during growth from childhood through young adulthood; however, engaging in LPA may enhance cardiac health in the young population.

Accelerometer-based sedentary time, light physical activity, and moderate-to-vigorous physical activity from childhood with arterial stiffness and carotid IMT progression: A 13-year longitudinal study of 1339 children

AIMS

We examined the longitudinal associations of sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous PA (MVPA) from childhood with carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness and carotid intima-media thickness (cIMT).

METHODS

We studied 1339 children, aged 11 years from Avon Longitudinal Study of Parents and Children, UK, followed up for 13 years. Accelerometer-based ST, LPA, and MVPA were assessed at ages 11, 15, and 24 years clinic visits. cfPWV and cIMT were measured with Vicorder and ultrasound, respectively, at ages 17 and 24 years.

RESULTS

Among 1339 [56.4% female] participants, mean ST increased from ages 11 through 24 years, while mean LPA and MVPA decreased. Persistently high ST tertile from childhood was associated with increased cfPWV progression, effect estimate 0.047 m/s; [(95% CI 0.005 to 0.090); p = 0.030], but not cIMT progression. Persistently high LPA tertile category was associated with decreased cfPWV progression in males -0.022 m/s; [(-0.028 to -0.017); p < 0.001] and females -0.027 m/s; [(-0.044 to -0.010); p < 0.001]. Cumulative LPA exposure decreased the odds of progressively worsening cfPWV [Odds ratio 0.994 (0.994-0.995); p < 0.0001] and cIMT. Persistent exposure to ≥60 min/day of MVPA was paradoxically associated with increased cfPWV progression in males 0.053 m/s; [(0.030 to 0.077); p < 0.001] and females 0.012 m/s; [(0.002 to 0.022); p = 0.016]. Persistent exposure to ≥60 min/day of MVPA was inversely associated with cIMT progression in females -0.017 mm; [(-0.026 to -0.009); p < 0.001].

CONCLUSION

LPA >3 h/day from childhood may attenuate progressively worsening vascular damage associated with increased ST in youth.

Mediating effect of fat mass, lean mass, blood pressure and insulin resistance on the associations of accelerometer-based sedentary time and physical activity with arterial stiffness, carotid IMT and carotid elasticity in 1574 adolescents

This study examined the mediating effect of total body fat mass, lean mass, blood pressure (BP) and insulin resistance on the associations of sedentary time (ST), light physical activity (LPA) and moderate-to-vigorous PA (MVPA) with carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT) and carotid elasticity in 1574 adolescents from the Avon Longitudinal Study of Parents and Children birth cohort, UK. ST, LPA and MVPA were assessed with ActiGraph accelerometer. ST and LPA were sex-categorised in tertiles as low (reference), moderate and high, while MVPA was categorised as <40 min/day (reference), 40-<60 min/day and ≥60 min/day. cfPWV, cIMT and carotid elasticity were measured with Vicorder and ultrasound. Fat mass and lean mass were assessed with dual-energy X-ray absorptiometry and homeostatic model assessment of insulin resistance (HOMA-IR) was computed. Mediation analyses structural equation models and linear mixed-effect models adjusted for cardiometabolic and lifestyle factors were conducted. Among 1574 adolescents [56.2% female; mean (SD) age 15.4 (0.24) years], 41% males and 17% females accumulated ≥60 min/day of MVPA. Higher ST was associated with lower cIMT partly mediated by lean mass. Higher LPA (standardized β = -0.057; [95% CI -0.101 to -0.013; p = 0.014]) and the highest LPA tertile were associated with lower cfPWV. BP had no significant mediating effect movement behaviour relations with vascular indices. Lean mass partially mediated associations of higher MVPA with higher cIMT (0.012; [0.007-0.002; p = 0.001], 25.5% mediation) and higher carotid elasticity (0.025; [0.014-0.039; p = 0.001], 28.1% mediation). HOMA-IR mediated the associations of higher MVPA with higher carotid elasticity (7.7% mediation). Engaging in ≥60 min/day of MVPA was associated with higher carotid elasticity. In conclusion, higher LPA was associated with lower arterial stiffness, but higher MVPA was associated with thicker carotid wall explained by higher lean mass.

Waist-circumference-to-height-ratio had better longitudinal agreement with DEXA-measured fat mass than BMI in 7237 children

BACKGROUND

The absolute agreement of surrogate measures of adiposity with dual-energy X-ray absorptiometry (DEXA)-measured body composition was examined.

METHODS

Over a 15-year follow-up, 7237 (3667 females) nine-year-old children from the Avon Longitudinal Study of Parents and Children (ALSPAC) UK birth cohort were included. Total fat mass (FM) and trunk FM were serially measured with DEXA at ages 9, 11, 15, 17, and 24 years. BMI and waist circumference-to-height ratio (WHtR) were computed. Pearson's correlations, intraclass correlations (ICC), and area under curve (AUC) analyses were conducted.

RESULTS

Over 15 years, BMI, total FM, and trunk FM, increased but WHtR was relatively stable. WHtR provided a better longitudinal absolute agreement [males ICC 0.84 (95% CI 0.84-0.85); females 0.81 (0.80-0.82)] than BMI [(males (0.65 (0.64-0.66); females 0.72 (0.71-0.73)] with total FM as well as trunk FM from ages 9-24 years. WHtR cut-point for predicting excess total FM (75th-95th percentile) was 0.50-0.53 in males [AUC 0.86-0.94, sensitivity 0.51-0.79 and specificity 0.93-0.95]. WHtR cut-point for predicting excess total FM (75th-95th percentile) was 0.52-0.54 in females [AUC 0.83-0.95, sensitivity 0.38-0.68 and specificity 0.92-0.95]. Results were similar with trunk FM.

CONCLUSION

WHtR is an inexpensive alternative to BMI for predicting FM in pediatrics.

IMPACT

Waist circumference-to-height ratio (WHtR) is a better adiposity surrogate measure than body mass index (BMI) in predicting fat mass and discriminating lean mass from childhood through young adulthood. BMI has been used as an inexpensive surrogate measure of adiposity in children for several decades. However, emerging findings suggest that BMI fails to discriminate between fat mass adiposity and lean mass. This is the first-ever longitudinal study in over 7000 children followed up for 15 years that identified WHtR as an inexpensive accurate measure that discriminates fat mass from lean mass that could replace BMI measure of obesity in pediatrics.

Increasing lipids with risk of worsening cardiac damage in 1595 adolescents: A 7-year longitudinal and mediation study

BACKGROUND AND AIMS

Longitudinal evidence on the associations of changes in lipids level with changes in cardiac structure and function in youth is limited due to few repeated echocardiography measures. This study examined whether changes in lipid levels from adolescence through young adulthood associate with the risk of cardiac damage progression and potential mechanistic pathways.

METHODS

From the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort, 1595 adolescents aged 17 years who had fasting plasma total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), and non-HDL-c measured at 17- and 24-year clinic visit were included. Echocardiography measured left ventricular mass indexed for height2.7 (LVMI2.7), and LV diastolic function from mitral E/A ratio (LVDF). LVMI2.7 ≥51 g/m2.7 and LVDF<1.5 were categorized as LV hypertrophy and LVD dysfunction, respectively. Multivariable adjusted associations were examined using generalized logit mixed-effect models and structural equation models for mediation analyses.

RESULTS

The prevalence of LV hypertrophy increased from 3.6% at baseline to 11.6% at follow-up in males and increased from 1.6% to 4.0% in females. The prevalence of LVD dysfunction increased from 7.8% at baseline to 16.6% at follow-up in males and increased from 10.3% to 15.4% in females. Each 1 mmol increase in total cholesterol (OR, 1.18; [95% CI, 1.09-1.27]), triglyceride (2.89; [1.54-5.43]), LDL-c (1.19; [1.08-1.32]), and non-HDL-c (1.21; [1.11-1.33]) was associated with higher odds of worsening LV hypertrophy progression over 7 years. Increased triglyceride was associated with the odds of progressively worsening LVD dysfunction (1.98; [1.06-3.71]). Increased HDL-c was not associated with the odds of cardiac structural and functional damage. Systolic blood pressure (12% mediation) and fat mass (25% mediation) partly mediated the associations of LDL-c with increased LVMI2.7.

CONCLUSIONS

Increased lipids may independently associate with the risk of progressively worsening structural and functional cardiac damage in youth but increased systolic blood pressure and fat mass explained circa forty percent of the relationship.

DEXA-based Fat Mass with the Risk of Worsening Insulin Resistance in Adolescents: A 9-Year Temporal and Mediation Study

CONTEXT

Surrogate measures of childhood and adolescent obesity have impaired the understanding of body composition's relationship with insulin resistance in the young population.

OBJECTIVES

We aim to examine the longitudinal associations of directly measured total fat mass, trunk fat mass, and lean mass with the risk of hyperglycaemia, hyperinsulinemia, and insulin resistance from ages 15-24 years, the mediation path through which lipids and inflammation influence insulin resistance and whether increased fat mass temporally precede insulin resistance.

METHODS

We studied 3160 adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort, who had complete dual-energy Xray absorptiometry measure and fasting blood samples at age 15 years and repeated measures at ages 17- and 24-years clinic visit. Fasting glucose >6.1 mmol/L, insulin >11.78 mU/L, and homeostatic model assessment for insulin resistance (HOMA-IR) ≥75th percentile were categorized as hyperglycaemia, hyperinsulinemia, and high insulin resistance, respectively. Longitudinal associations were examined with generalized logit-mixed effect models, whilst mediation and temporal path analyses were examined using structural equation models, adjusting for cardiometabolic and other lifestyle factors.

RESULTS

Among 3160 participants (51% female), fat mass and lean mass increased linearly in both males and females while glucose, insulin, and HOMA-IR had a U-shaped course from age 15 through 24 years. After full adjustment, each 1 kg cumulative increase in total fat mass [odds ratio 1.12 (95% confidence interval 1.11-1.13)] and trunk fat mass [1.21 (1.19-1.23)] from ages 15 through 24 years were associated with a progressively worsening risk of high insulin resistance as well as hyperglycaemia and hyperinsulinemia. The association of increased total fat mass with increased insulin resistance was partly mediated by triglycerides (9% mediation). In the temporal path analysis, higher total fat mass at age 15 years was associated with higher insulin resistance at 17 years, but not vice versa. Higher total fat mass at 17 years was bi-directionally associated with higher insulin resistance at 24 years.

CONCLUSION

Mid-adolescence may be an optimal time for interrupting the worsening fat mass-insulin resistance pathologic cycle and attenuating the risk of progressively worsening metabolic dysfunction before young adulthood.

Effects of accelerometer-based sedentary time and physical activity on DEXA-measured fat mass in 6059 children

Globally, childhood obesity is on the rise and the effect of objectively measured movement behaviour on body composition remains unclear. Longitudinal and causal mediation relationships of accelerometer-based sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with dual-energy X-ray absorptiometry-measured fat mass were examined in 6059 children aged 11 years followed-up until age 24 years from the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort. Over 13-year follow-up, each minute/day of ST was associated with 1.3 g increase in fat mass. However, each minute/day of LPA was associated with 3.6 g decrease in fat mass and each minute/day of MVPA was associated with 1.3 g decrease in fat mass. Persistently accruing ≥60 min/day of MVPA was associated with 2.8 g decrease in fat mass per each minute/day of MVPA, partly mediated by decrease insulin and low-density lipoprotein cholesterol. LPA elicited similar and potentially stronger fat mass-lowering effect than MVPA and thus may be targeted in obesity and ST prevention in children and adolescents, who are unable or unwilling to exercise.