Percentile Units Research Articles

Intraindividual Discordance Between Remnant Cholesterol and Low-Density Lipoprotein Cholesterol Associated With Incident Stroke: Results From 2 National Cohorts.

The atherogenic effect of remnant cholesterol is being increasingly acknowledged. This study aimed to explore the association of discordance between remnant cholesterol and low-density lipoprotein cholesterol with stroke onset using 2 Chinese national cohorts. We studied 11 139 participants from CHARLS (China Health and Retirement Longitudinal Study) and 5993 participants from CHNS (China Health and Nutrition Survey) aged 45 years or older. The discordance between remnant cholesterol and low-density lipoprotein cholesterol was defined using the difference in percentile units (>15 units). There were 988 (8.9%) and 128 (2.1%) stroke events reported during follow-up in the 2 cohorts. Elevated remnant cholesterol was significantly associated with a higher risk of total stroke in 2 cohorts. After adjusting for remnant cholesterol level, the discordantly high remnant cholesterol group was significantly associated with an increased stroke risk (CHARLS: subdistribution hazard ratio [sHR], 1.31 [95 CI, 1.10-1.55]; CHNS: sHR, 1.84 [95 CI, 1.15-3.08]) compared with the discordantly low group. Consistent results were shown even among those with optimal low-density lipoprotein cholesterol level. The discordance between remnant cholesterol and low-density lipoprotein cholesterol, representing the intraindividual discrepancy, is significantly associated with stroke onset among Chinese adults.

Remnant cholesterol and risk of incident hypertension: a population-based prospective cohort study.

Remnant cholesterol (RC) has been associated with atherosclerotic cardiovascular disease, but its relationship with hypertension remains unclear. This prospective cohort study aimed to investigate the association between RC and subsequent hypertension risk. Data from the UK Biobank, comprising 295,062 participants initially free of hypertension, were analyzed. Cox proportional hazards regression assessed the association between RC quartiles and hypertension risk. Discordance analysis evaluated the risk of hypertension in discordant/concordant groups of RC and low-density lipoprotein cholesterol (LDL-C) using the difference in percentile units (>10 units). Restricted cubic spline curves were used to model the relationship between RC and hypertension risk. The mean ± SD age of participants was 55.1 ± 8.1 years, with 40.6% being men and 94.7% White. During a median follow-up of 12.8 years, 39,038 participants developed hypertension. Comparing extreme quartiles of RC, the hazard ratio (HR) for incident hypertension was 1.20 (95% CI: 1.17-1.24). After adjusting for traditional risk factors, each 1 mmol/L increase in RC levels was associated with a 27% higher risk of incident hypertension (HR: 1.27; 95% CI: 1.23-1.31). The discordant group with high RC/low LDL-C exhibited a higher risk of incident hypertension compared to the concordant group (HR: 1.06; 95% CI: 1.03-1.09). Spline curves further demonstrated a positive association between RC and the risk of incident hypertension. We concluded that elevated RC emerged as an independent risk factor of incident hypertension, extending beyond traditional risk factors. Monitoring RC levels and implementing interventions to lower RC may have potential benefits in preventing hypertension.

Lipoprotein(a) and functional outcome of acute ischemic stroke when discordant with low-density lipoprotein cholesterol.

Several studies have indicated that residual cardiovascular risk might be associated with elevated lipoprotein(a) [Lp(a)] even in the setting of controlled low-density lipoprotein cholesterol (LDL-C). We aimed to prospectively examine the association between Lp(a) and unfavorable functional outcome among patients with acute ischemic stroke when Lp(a) and LDL-C were discordant. Based on samples from the Infectious Factors, Inflammatory Markers and Prognosis of Acute Ischemic Stroke study, 973 patients with baseline plasma Lp(a) levels were included. The primary outcome was the composite outcome of death or major disability (modified Rankin Scale score of 3-6) at 6months. Logistic regression models were used to estimate the risk for the primary outcome. Discordance analyses were performed, using difference in percentile units (>10units), to detect the relative risk when Lp(a) and LDL-C were discordant. In total, 201 (20.7%) participants experienced major disability or death at 6months. The multivariable-adjusted odds ratio (OR) for the highest quartile was 1.88 [95% confidence interval (CI): 1.16-3.04] compared with the lowest quartile. Each 1-SD higher log-Lp(a) was associated with a 23% increased risk (95% CI: 2%-47%) for the primary outcome. Compared with the concordant group, the high Lp(a)/low LDL-C discordant group was associated with increased risk for the primary outcome (adjusted OR: 1.59, 95% CI: 1.01-2.52). Elevated plasma Lp(a) levels were associated with increased risk of major disability and death at 6months. Discordantly high Lp(a)/low LDL-C was associated with an unfavorable functional outcome, supporting the predictive potential of plasma Lp(a) after ischemic stroke, especially when discordant with LDL-C. Key messages What is already known on this topic Previous studies have indicated that a positive association between increased lipoprotein(a) [Lp(a)] and cardiovascular disease risk remained even in patients who achieved controlled low-density lipoprotein cholesterol (LDL-C) levels. The findings of studies exploring the association between Lp(a) and unfavorable clinical outcomes of stroke were inconsistent, and whether Lp(a) can predict the risk of unfavorable functional outcome in stroke patients when Lp(a) and LDL-C levels are discordant remains unknown. What this study adds Elevated plasma Lp(a) levels were associated with increased risk of major disability and death at 6months beyond LDL-C levels in acute ischemic stroke patients. How this study might affect research, practice, or policy The combination of LDL-C-lowering therapies and Lp(a)-lowering therapies may have better clinical efficacy for patients with ischemic stroke, and it is of great clinical interest to further explore this possibility in dedicated randomized trials.

Discordance Between Self-Reported and Performance-Based Physical Function in Patients Who Have Knee Osteoarthritis: Associations With Pain Intensity and Negative Affect

BackgroundAlthough self-reported measures of physical disability are strong indication criterion for total knee arthroplasty (TKA) in painful knee osteoarthritis (OA), some patients may report greater-than-observed disability. Contributing factors to this discordance are relatively unexplored. We aimed to examine whether pain and negative affect, including anxiety and depression, were associated with the discordance of self-reported measures with performance-based measures (PPM) of physical function. MethodsWe used cross-sectional data (n = 212) from two randomized rehabilitation trials in knee OA. All patients were assessed for knee pain intensity and symptoms of anxiety and depression. Self-reported function was assessed by the Western Ontario and McMaster Universities Arthritis Index (WOMAC) physical-function subscale. Objective performance-based measures (PPMs) of physical function were assessed by timed gait and stair tests. Continuous discordance scores were quantified by the difference in percentiles between WOMAC and PPMs (WOMAC-PPM), where a positive discordance, WOMAC-PPM >0, implied greater perceived than observed disability. ResultsAround 1 in 4 patients had >20 percentile units in WOMAC-PPM discordance. In Bayesian regression analyses, knee pain intensity had >99% posterior probability of positive associations with WOMAC-PPM discordance. Among patients awaiting TKA, anxiety intensity had approximately 99% probability of positive associations with discordance, and these associations had >65% probability of exceeding 10 percentile units. In contrast, depression had low (79% to 88%) probability of any association with discordance. ConclusionIn patients who have knee OA, a sizable proportion reported substantially greater physical disability than actually observed. Pain and anxiety intensity, but not depression, were meaningful predictors of this discordance. If validated, our findings may help in refining patient selection criteria for TKA.

Impact of OSA treatment success on changes in hypertension and obesity: A retrospective cohort study

ObjectivePediatric obstructive sleep apnea (OSA) has been shown to lead to the development of chronic cardiometabolic conditions, including obesity and cardiovascular disease. We sought to describe the impact of the success of continuous positive airway pressure (CPAP) and surgery, common treatment options for pediatric OSA, on cardiometabolic conditions. MethodsA retrospective review of patients (≤18 years) diagnosed with OSA based on a polysomnogram at a tertiary care pediatric otolaryngology practice from 2015 to 2019 was conducted. Clinical data, including the systolic blood pressure (SBP) values, body mass index (BMI), overall apnea/hypopnea index (AHI) values, and CPAP compliance, were collected. Linear mixed-effects models were developed to observe the relationship between the clinical measurements of each comorbidity and OSA treatment modalities. Results414 patients were included. BMI and SBP measures were collected for 230 and 184 patients respectively. The difference-in-difference estimate for the SBP z-score percentile after successful treatment was −5.5 ± 2.1 percentile units per 100 days. The difference-in-difference estimate for SBP z-score percentile after successful CPAP treatment was −13.2 ± 5.1 percentile units per 100 days while the estimate after successful surgical treatment was −4.6 ± 2.4 percentile units per 100 days. No significant differences were found between clinical measures for obese patients in any treatment cohort. ConclusionsSuccessful OSA management was shown to have a positive impact on SBP in hypertensive patients and no impact on BMI in obese patients. In hypertensive patients, CPAP success tripled improvements in SBP z-score percentile compared to surgical treatment success.

Remnant cholesterol predicts cardiovascular disease beyond LDL and ApoB: a primary prevention study.

Emerging evidence suggests that remnant cholesterol (RC) promotes atherosclerotic cardiovascular disease (ASCVD). We aimed to estimate RC-related risk beyond low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apoB) in patients without known ASCVD. We pooled data from 17 532 ASCVD-free individuals from the Atherosclerosis Risk in Communities study (n = 9748), the Multi-Ethnic Study of Atherosclerosis (n = 3049), and the Coronary Artery Risk Development in Young Adults (n = 4735). RC was calculated as non-high-density lipoprotein cholesterol (non-HDL-C) minus calculated LDL-C. Adjusted Cox models were used to estimate the risk for incident ASCVD associated with log RC levels. We also performed discordance analyses examining relative ASCVD risk in RC vs. LDL-C discordant/concordant groups using difference in percentile units (>10 units) and clinically relevant LDL-C targets. The mean age of participants was 52.3 ± 17.9 years, 56.7% were women and 34% black. There were 2143 ASCVD events over the median follow-up of 18.7 years. After multivariable adjustment including LDL-C and apoB, log RC was associated with higher ASCVD risk [hazard ratio (HR) 1.65, 95% confidence interval (CI) 1.45-1.89]. Moreover, the discordant high RC/low LDL-C group, but not the low RC/high LDL-C group, was associated with increased ASCVD risk compared to the concordant group (HR 1.21, 95% CI 1.08-1.34). Similar results were shown when examining discordance across clinical cutpoints. In ASCVD-free individuals, elevated RC levels were associated with ASCVD independent of traditional risk factors, LDL-C, and apoB levels. The mechanisms of RC association with ASCVD, surprisingly beyond apoB, and the potential value of targeted RC-lowering in primary prevention need to be further investigated.

Random-effects linear model application to herd-level assessment of bovine hepatic trace mineral concentrations.

To evaluate the utility of random-effects linear modeling for herd-level evaluation of trace mineral status, we performed a retrospective analysis of the results for trace mineral testing of bovine liver samples submitted to the Michigan State University Veterinary Diagnostic Laboratory between 2011 and 2017. Our aim was to examine random-effects models for their potential utility in improving interpretation with minimal sample numbers. The database consisted of 1,658 animals distributed among 121 herds. Minerals were assayed by inductively coupled plasma-mass spectroscopy, and included cobalt, copper, iron, molybdenum, manganese, selenium, and zinc. Intraclass correlation coefficients for each mineral were significantly different (p < 0.001) from zero and ranged from 0.38 for manganese to 0.82 for selenium, indicating that the strength of herd effects, which are presumably related to diet, vary greatly by mineral. Analysis of the distribution and standard errors of best linear unbiased predictor (BLUP) values suggested that testing 5-10 animals per herd could place herds within 10 percentile units across the population of herds with 70-95% confidence, the confidence level varying among minerals. Herd means were generally similar to BLUPs, suggesting that means could be reasonably compared to BLUPs with respect to the distributions reported here. However, caution in interpreting means relative to BLUPs should be exercised when animal numbers are small, the standard errors of the means are large, and/or the values are near the extremes of the distribution.

An open-label randomized controlled trial of DMARD withdrawal in RA patients achieving therapeutic response with certolizumab pegol combined with DMARDs

The objective of this trial was to compare effectiveness of certolizumab pegol added to conventional synthetic DMARDs (csDMARDs) in RA patients, followed by continuing vs discontinuing background csDMARDs after treatment response. Patients with active RA who had certolizumab pegol added to their existing csDMARD regimen due to inadequate response were eligible. At 3 or 6 months, patients who achieved a change (Δ) in DAS28 of ⩾1.2 were randomized to continue combination therapy (COMBO) or withdraw csDMARD therapy (MONO) (unblinded). The primary outcome was non-inferiority of stopping vs continuing csDMARD(s) in terms of maintaining ΔDAS28 ⩾ 1.2 or achieving DAS28 low disease activity at 18 months (non-inferiority margin: 15 percentile units). A total of 125 patients were enrolled, 88 randomized to COMBO (n = 43) or MONO (n = 45). No significant differences were observed between groups in baseline age, gender, race, RF status or prior biologics (16% vs 11%). Although the rate of ΔDAS28 ⩾ 1.2 and/or DAS28 low disease activity achievement at 18 months was clinically comparable between the two groups (72% vs 69%), non-inferiority assumptions were not met [absolute risk difference (upper limit of 90% CI): 2.6% (19.1%)]. Similar baseline-adjusted improvements were seen in DAS28 (COMBO vs MONO: -2.3 vs -2.1; P = 0.49) and all endpoints were not statistically different including 59% vs 56% achieved DAS28 low disease activity, 69% vs 59% ΔDAS28 ⩾ 1.2, and 41% each remission. Among RA patients achieving a therapeutic response on combination therapy with certolizumab pegol and csDMARDs, withdrawing csDMARDs was not non-inferior to maintaining csDMARDs but improvements were sustained in both groups at 18 months.

High cardiovascular risk patients benefit more from bariatric surgery than low cardiovascular risk patients.

Atherosclerotic cardiovascular disease (ASCVD) and Framingham risk scores (FRS) are used to calculate 10-year risk of coronary death, nonfatal myocardial infarction, or fatal/nonfatal stroke. Our goal is to evaluate the association between preoperative cardiovascular risk and weight loss. We retrospectively reviewed bariatric surgeries from 2010 to 2016. Patients who met criteria for calculating 10-year ASCVD score and FRS were included. Data collected included baseline demographics, perioperative parameters, and postoperative outcomes at 12months. Simple linear regression and multiple linear regression models were applied to test influence of individual or multiple factors of interest on 12-month weight loss outcomes. Of 1330 bariatric patients studied, 360 patients met criteria for ASCVD and FRS calculation. Sleeve gastrectomy (LSG) was the most prevalent surgery 63.05%, followed by Roux-en-Y gastric bypass (LRYGB) 20.55%, revision procedures 11.9%, and adjustable gastric banding (LAGB) 4.4%. Initial BMI was 42.71 ± 7.85kg/m2 for females and 42.72k ± 7.42kg/m2 for males, with a 12-month percentage of estimated BMI loss (%EBMIL) of 66.51% in females and 60.29% in males. Preoperative 10-year ASCVD score was higher in males than females with a 34.73% relative risk reduction (RRR) in males and 35.3% RRR in females at 12-month follow-up. Regarding FRS, preoperative risk was 33.13 ± 21.1% in males and 15.71 ± 14.52% in females, with an RRR of 25.8% in males and 32.2% in females. Univariate analysis of preoperative FRS and %EBMIL showed that for every percentage unit increase in the patient's preoperative FRS, %EBMIL decreases 0.31 percentile unit (P < 0.001). Furthermore, preoperative ASCVD score is also significantly associated with %EMBIL-for every percentage unit increase in preoperative ASCVD score, %EBMIL decreases 0.42 percentile credits. Study results suggest ASCVD and FRS are equally reduced after bariatric surgery, especially after LSG and LRYGB. Moreover, preoperative FRS and ASCVD risk score showed an inversely proportional relationship with %EBMIL loss at 12 months.

Abstract 194: Discordance in Apolipoprotein B vs. non-HDL-C and the Cholesterol-Enriched Phenotype: Insights From the National Health and Nutrition Examination Survey (NHANES) 2011-2012

Background: Apolipoprotein B (apoB) levels in plasma are proportional to the number of all atherogenic, non-high-density lipoprotein (HDL) particles. Non-HDL-C concentration - the aggregate cholesterol carried by apoB-containing particles - is usually highly correlated with apoB levels. This study aimed to describe individuals with discordance between these lipid measures, especially apoB&lt;non-HDL-C discordance, as there are few prior data on this cholesterol-enriched particle phenotype. Methods: We analyzed 2,804 participants of NHANES 2011-2012, a nationally representative US cross-sectional survey with direct apoB and standard lipid fasting measurements. We assigned population percentiles to non-HDL-C and apoB levels and created groups with 5-10 or &gt;10 percentile units of discordantly low apoB (apoB&lt;non-HDL-C: “cholesterol-enriched”) or high apoB (apoB&gt;non-HDL-C: “cholesterol-depleted”). We compared lipids levels and other clinical characteristics across groups. Results: Discordance &gt;5 percentile units was present in 50.9% of individuals. Compared with the cholesterol-depleted group, the cholesterol-enriched phenotype was characterized by a lower prevalence of obesity, diabetes, and hypertension. We found higher levels of low-density lipoprotein cholesterol (LDL-C), non-HDL-C, and HDL-C in cholesterol-enriched compared with cholesterol-depleted groups, whereas triglycerides were similar across groups. Lipid levels were consistent after excluding individuals on lipid-lowering therapy. Conclusion: Despite having higher levels of non-HDL-C and LDL-C, the cholesterol-enriched phenotype had a more favorable cardiovascular risk factor profile compared with the cholesterol-depleted phenotype. Triglycerides were notably low and similar across groups. Evaluation for discordance at both ends of the spectrum may provide additional prognostic information on CVD risk, but further outcomes studies are needed.

Pacific kids DASH for health (PacDASH) randomized, controlled trial with DASH eating plan plus physical activity improves fruit and vegetable intake and diastolic blood pressure in children.

Pacific Kids DASH for Health (PacDASH) aimed to improve child diet and physical activity (PA) level and prevent excess weight gain and elevation in blood pressure (BP) at 9 months. PacDASH was a two-arm, randomized, controlled trial (ClinicalTrials.gov: NCT00905411). Eighty-five 5- to 8-year-olds in the 50th-99th percentile for BMI were randomly assigned to treatment (n=41) or control (n=44) groups; 62 completed the 9-month trial. Sixty-two percent were female. Mean age was 7.1±0.95 years. Race/ethnicity was Asian (44%), Native Hawaiian or Other Pacific Islander (28%), white (21%), or other race/ethnicity (7%). Intervention was provided at baseline and 3, 6 and 9 months, with monthly supportive mailings between intervention visits, and a follow-up visit at 15 months to observe maintenance. Diet and PA were assessed by 2-day log. Body size, composition, and BP were measured. The intervention effect on diet and PA, body size and composition, and BP by the end of the intervention was tested using an F test from a mixed regression model, after adjustment for sex, age, and ethnic group. Fruit and vegetable (FV) intake decreased less in the treatment than control group (p=0.04). Diastolic BP (DBP) was 12 percentile units lower in the treatment than control group after 9 months of intervention (p=0.01). There were no group differences in systolic BP (SBP) or body size/composition. The PacDASH trial enhanced FV intake and DBP, but not SBP or body size/composition.

The fractionalization of physical activity throughout the week is associated with the cardiometabolic health of children and youth.

BackgroundThe influence of the fractionalization of moderate- to vigorous- intensity physical activity (MVPA) throughout the week on the health of children is unknown. We compared cardiometabolic risk factors in physically active children who accumulated their weekly MVPA in different patterns.MethodsWe studied 745 participants aged 6–19 years. MVPA was measured using accelerometers over 7 days. Three groups were created: Insufficiently Active, <60 minutes/day of MVPA on average; Infrequently Active, ≥60 minutes/day of MVPA on average but exceeding the 60 minute target <5 days; and Frequently Active, ≥60 minutes/day MVPA on average and exceeding the 60 minute target ≥5 days. Percentile scores for 8 cardiometabolic risk factors were determined.ResultsThe least favorable cardiometabolic risk factor profile was observed in the Insufficiently Active group. The Frequently Active group had more favorable (5–6 percentile unit difference) diastolic blood pressure, HDL-cholesterol, insulin resistance, and metabolic syndrome scores than the Infrequently Active group, although only the difference for insulin resistance was statistically significant (P < 0.05). These differences remained after controlling for the weekly volume of MVPA.ConclusionThe fractionalization of MVPA throughout the week was associated with insulin resistance.

Low-Density Lipoprotein Cholesterol versus Particle Number in Middle School Children

To characterize lipids and lipoproteins in a diverse school-based cohort and identify features associated with discordance between low-density lipoprotein cholesterol (LDL-C) and LDL particle (LDL-P). Sixth-grade children enrolled in the HEALTHY trial (n = 2384; mean age 11.3 ± 0.6 years; 54.2% female) were evaluated for standard lipids, lipoprotein particles measured by nuclear magnetic resonance, and homeostatic model of insulin resistance. Characteristics of subgroups with values of LDL-C and LDL-P discordant by >20 percentile units, an amount reasoned to be clinically significant, were compared. Four-hundred twenty-eight (18%) of children were in the LDL-P < LDL-C subgroup and 375 (16%) in the LDL-P > LDL-C subgroup. Those with LDL-P > LDL-C had significantly greater body mass index, waist circumference, homeostatic model of insulin resistance, triglycerides, systolic and diastolic blood pressure, and reflected a greater Hispanic ethnic composition but fewer of black race than both the concordant (LDL-P ≅ LDL-C) and opposite discordant (LDL-P < LDL-C) subgroups. There is as much lipoprotein cholesterol compositional heterogeneity in sixth graders as has been described in adults and a discordant atherogenic phenotype of LDL-P > LDL-C, common in obesity, is often missed when only LDL-C is considered. Conversely, many children with moderate-risk cholesterol measures (75th to 99th percentile) have a lower LDL-P burden.

SP3-12 Predictors of 10-year mortality in a community-dwelling population of Brazilian elderly: the BambuÍ cohort study of ageing

IntroductionPredictors of mortality in old age have received much attention in the last 2 decades, but few studies have examined predictors of mortality in socioeconomically disadvantaged elderly populations in middle...

Clinical implications of discordance between low-density lipoprotein cholesterol and particle number

The amount of cholesterol per low-density lipoprotein (LDL) particle is variable and related in part to particle size, with smaller particles carrying less cholesterol. This variability causes concentrations of LDL cholesterol (LDL-C) and LDL particles (LDL-P) to be discordant in many individuals. LDL-P measured by nuclear magnetic resonance spectroscopy, calculated LDL-C, and carotid intima-media thickness (IMT) were assessed at baseline in the Multi-Ethnic Study of Atherosclerosis, a community-based cohort of 6814 persons free of clinical cardiovascular disease (CVD) at entry and followed for CVD events (n = 319 during 5.5-year follow-up). Discordance, defined as values of LDL-P and LDL-C differing by ≥ 12 percentile units to give equal-sized concordant and discordant subgroups, was related to CVD events and to carotid IMT in models predicting outcomes for a 1 SD difference in LDL-C or LDL-P, adjusted for age, gender, and race. LDL-C and LDL-P were associated with incident CVD overall: hazard ratios (HR 1.20, 95% CI [CI] 1.08-1.34; and 1.32, 95% CI 1.19-1.47, respectively, but for those with discordant levels, only LDL-P was associated with incident CVD (HR 1.45, 95% CI 1.19-1.78; LDL-C HR 1.07, 95% CI 0.88-1.30). IMT also tracked with LDL-P rather than LDL-C, ie, adjusted mean IMT of 958, 932, and 917 microm in the LDL-P > LDL-C discordant, concordant, and LDL-P < LDL-C discordant subgroups, respectively, with the difference persisting after adjustment for LDL-C (P = .002) but not LDL-P (P = .60). For individuals with discordant LDL-C and LDL-P levels, the LDL-attributable atherosclerotic risk is better indicated by LDL-P.

Sources of greater fetal vulnerability to airborne polycyclic aromatic hydrocarbons among African Americans

BackgroundThis study attempted to clarify the household and mother's lifestyle factors that contribute to the greater fetal vulnerability of African-American individuals to airborne polycyclic aromatic hydrocarbons (PAH).MethodsNon-smoking pregnant women with...

Hypertension and obstructive sleep apnea in Caucasian children.

To evaluate the prevalence of hypertension and/or left ventricular hypertrophy (LVH) in children with a diagnosis of obstructive sleep apnea (OSA). A cross-sectional case series of consecutive, otherwise healthy children aged > 4 years, with polysomnography-proven OSA [apnea hypopnea index (AHI) > 1.5/h] is described. Echocardiography was performed on all subjects and left ventricular mass was calculated. Study subjects underwent additional investigation with 24-h ambulatory blood pressure (BP) monitoring. Thirty children (21 males) were studied. Mean age was 8.9 years. Mean body mass index was 19.87 kg/cm(2). Mean AHI was 14.3/h. 10/30 (33%) of the study population met criteria for pre-hypertension (n = 3) or masked hypertension (n = 7) based on standard ambulatory monitoring criteria. All 10 children had systolic hypertension throughout the night with 5 of these also having elevated daytime systolic readings. There was a relationship between AHI and BP showing an increase of 1.162 percentile units in mean diastolic night BP (age, gender and height specific) per unit increase in AHI (P = 0.018). There were no subjects with LVH and/or right ventricular hypertrophy. In our population of otherwise healthy Caucasian children, there was a high prevalence of hypertension that would not have been identified using standard office/clinic protocols.

SYSGRAN: UM SISTEMA DE CÓDIGO ABERTO PARA ANÁLlSES GRANULOMÉTRICAS DO SEDIMENTO

SysGran is an easy-to-use specific software for granulometric analysis of sediments, which includes a rich graphical output. The software is now available under GNU license, meaning that it is free for any use and can be freely modified and improved. The software has been designed to maximize speed of analysis and is able to analyze hundreds of samples in a few seconds, together with many types of graphics. The results of statistical analysis of the sediment includes Folk &amp; Ward graphical methods (among others) as well as methods of moments (mean, median, sorting, skewness, curtosis), grain size fractions (gravel, sand, silt and clay percentages), verbal classification, main percentile units and data for cumulative frequency curve plot using other graphical softwares.

Pesticide residues in food--acute dietary exposure.

Consumer risk assessment is a crucial step in the regulatory approval of pesticide use on food crops. Recently, an additional hurdle has been added to the formal consumer risk assessment process with the introduction of short-term intake or exposure assessment and a comparable short-term toxicity reference, the acute reference dose. Exposure to residues during one meal or over one day is important for short-term or acute intake. Exposure in the short term can be substantially higher than average because the consumption of a food on a single occasion can be very large compared with typical long-term or mean consumption and the food may have a much larger residue than average. Furthermore, the residue level in a single unit of a fruit or vegetable may be higher by a factor (defined as the variability factor, which we have shown to be typically x3 for the 97.5th percentile unit) than the average residue in the lot. Available marketplace data and supervised residue trial data are examined in an investigation of the variability of residues in units of fruit and vegetables. A method is described for estimating the 97.5th percentile value from sets of unit residue data. Variability appears to be generally independent of the pesticide, the crop, crop unit size and the residue level. The deposition of pesticide on the individual unit during application is probably the most significant factor. The diets used in the calculations ideally come from individual and household surveys with enough consumers of each specific food to determine large portion sizes. The diets should distinguish the different forms of a food consumed, eg canned, frozen or fresh, because the residue levels associated with the different forms may be quite different. Dietary intakes may be calculated by a deterministic method or a probabilistic method. In the deterministic method the intake is estimated with the assumptions of large portion consumption of a 'high residue' food (high residue in the sense that the pesticide was used at the highest recommended label rate, the crop was harvested at the smallest interval after treatment and the residue in the edible portion was the highest found in any of the supervised trials in line with these use conditions). The deterministic calculation also includes a variability factor for those foods consumed as units (eg apples, carrots) to allow for the elevated residue in some single units which may not be seen in composited samples. In the probabilistic method the distribution of dietary consumption and the distribution of possible residues are combined in repeated probabilistic calculations to yield a distribution of possible residue intakes. Additional information such as percentage commodity treated and combination of residues from multiple commodities may be incorporated into probabilistic calculations. The IUPAC Advisory Committee on Crop Protection Chemistry has made 11 recommendations relating to acute dietary exposure.

Estimation of urban runoff and water quality using remote sensing and artificial intelligence

Water quality and quantity of runoff are strongly dependent on the landuse and landcover (LULC) criteria. In this study, we developed a more improved parameter estimation procedure for the environmental model using remote sensing (RS) and artificial intelligence (AI) techniques. Landsat TM multi-band (7bands) and Korea Multi-Purpose Satellite (KOMPSAT) panchromatic data were selected for input data processing. We employed two kinds of artificial intelligence techniques, RBF-NN (radial-basis-function neural network) and ANN (artificial neural network), to classify LULC of the study area. A bootstrap resampling method, a statistical technique, was employed to generate the confidence intervals and distribution of the unit load. SWMM was used to simulate the urban runoff and water quality and applied to the study watershed. The condition of urban flow and non-point contaminations was simulated with rainfall-runoff and measured water quality data. The estimated total runoff, peak time, and pollutant generation varied considerably according to the classification accuracy and percentile unit load applied. The proposed procedure would efficiently be applied to water quality and runoff simulation in a rapidly changing urban area.