Aerosol-Cloud-Precipitation Interactions in the Context of Convective Self-Aggregation.

We investigate the sensitivity of self-aggregated radiative-convective-equilibrium cloud-resolving model simulations to the cloud condensation nuclei (CCN) concentration. Experiments were conducted on a long (2,000-km × 120-km) channel domain, allowing the emergence of multiple convective clusters and dry regions of subsidence. Increasing the CCN concentration leads to increased moisture in the dry regions, increased midlevel and upper level clouds, decreased radiative cooling, and decreased precipitation. We find that these trends follow from a decrease in the strength of the self-aggregation as measured by the moist static energy (MSE) variance. In our simulations, precipitation is correlated, both locally and in total, with the distribution of MSE anomalies. We thus quantify changes in the adiabatic/diabatic contributions to MSE anomalies (Wing & Emanuel, 2014, https://doi.org/10.1002/2013MS000269) and relate those changes to changes in precipitation. Through a simple two-column conceptual model, we argue that the reduction in precipitation can be explained thermodynamically by the reduction in mean net radiative cooling and mechanistically by the weakening of the area-weighted radiatively driven subsidence velocity-defined as the ratio of the total radiative cooling over the dry regions and the static stability. We interpret the system's response to increasing CCN as a thermodynamically constrained realization of an aerosol indirect effect on clouds and precipitation.

Racial disparities in adult all-cause and cause-specific mortality among us adults: mediating and moderating factors.

BACKGROUND: Studies uncovering factors beyond socio-economic status (SES) that would explain racial and ethnic disparities in mortality are scarce. METHODS: Using prospective cohort data from the Third National Health and Nutrition Examination Survey (NHANES III), we examined all-cause and cause-specific mortality disparities by race, mediation through key factors and moderation by age (20-49 vs. 50+), sex and poverty status. Cox proportional hazards, discrete-time hazards and competing risk regression models were conducted (N = 16,573 participants, n = 4207 deaths, Median time = 170 months (1-217 months)). RESULTS: Age, sex and poverty income ratio-adjusted hazard rates were higher among Non-Hispanic Blacks (NHBs) vs. Non-Hispanic Whites (NHW). Within the above-poverty young men stratum where this association was the strongest, the socio-demographic-adjusted HR = 2.59, p < 0.001 was only partially attenuated by SES and other factors (full model HR = 2.08, p = 0.003). Income, education, diet quality, allostatic load and self-rated health, were among key mediators explaining NHB vs. NHW disparity in mortality. The Hispanic paradox was observed consistently among women above poverty (young and old). NHBs had higher CVD-related mortality risk compared to NHW which was explained by factors beyond SES. Those factors did not explain excess risk among NHB for neoplasm-related death (fully adjusted HR = 1.41, 95 % CI: 1.02-2.75, p = 0.044). Moreover, those factors explained the lower risk of neoplasm-related death among MA compared to NHW, while CVD-related mortality risk became lower among MA compared to NHW upon multivariate adjustment. CONCLUSIONS: In sum, racial/ethnic disparities in all-cause and cause-specific mortality (particularly cardiovascular and neoplasms) were partly explained by socio-demographic, SES, health-related and dietary factors, and differentially by age, sex and poverty strata.

White blood cell inflammatory markers are associated with depressive symptoms in a longitudinal study of urban adults.

Total white blood cell count (TWBCC) and percentage (%) composition of lymphocytes (PL) or neutrophils (PN) are linked to mid- and late-life depression, though sex-specific temporal relationships between those inflammatory markers and depressive symptoms remain unclear. The association between inflammation and depressive symptoms in longitudinal data on ethnically and socioeconomically diverse urban adults was examined with two hypotheses. In hypothesis 1, we examined the relationship between TWBCC, PL and PN with change in level of depressive symptoms from baseline to follow-up, stratifying by sex. In hypothesis 2, we examined reverse causality, by testing the relationship of depressive symptoms with change in TWBCC, PL and PN. Multiple linear mixed-effects regression models were performed to examine both the hypotheses. The sample sizes of participants (n) and repeated observations (n') were: Hypothesis 1 (n=2009; n'=3501); Hypothesis 2 (n=2081; n'=3560). Among key findings (Hypothesis 1), in women, higher TWBCC was linked to a faster increase in depressive symptom total score (γ1112±s.e.: +0.81±0.28, P=0.003), with a slower increase over time in the positive affect subdomain coupled with faster increases in depressed affect and somatic complaints. Among women, baseline score on somatic complaints was positively associated with low PN (γ01a=+1.61±0.48, P<0.001) and high PL (γ01a=+1.16±0.45, P=0.011), whereas baseline score on positive affect was inversely related to higher PL (γ01a=-0.69±0.28, P=0.017). Results among men indicated that there was a positive cross-sectional relationship between low TWBCC and depressive symptoms, depressed affect and an inverse cross-sectional relationship with positive affect. However, over time, a low TWBCC in men was linked to a higher score on positive affect. There was no evidence of a bi-directional relationship between WBC parameters and depressive symptoms (Hypothesis 2). In sum, TWBCC and related markers were linked to depressive symptoms, mostly among women. Further longitudinal studies are needed to replicate this sex-specific association.

Total serum cholesterol, atherogenic indices and their longitudinal association with depressive symptoms among US adults.

Serum cholesterol, both total and lipoprotein fractions, has been associated with mid- and late-life depression. Using longitudinal data on a large and ethnically diverse sample of urban adults, the associations of serum lipid profile measured by high or low total cholesterol (TC; >200 mg dl(-1); <160 mg dl(-1)) and by atherogenic indices, namely high total cholesterol and low-density lipoprotein cholesterol relative to high-density lipoprotein cholesterol, with change in total and domain-specific depressive symptoms over time were examined. Findings were compared by sex. (Hypothesis 1) In addition, baseline depressive symptoms as predictors for longitudinal change in lipid profile trajectory were tested. (Hypothesis 2) Mixed-effects regression analyses stratified by sex was used. Sample sizes of participants (n) and repeated observations (n') were: Hypothesis 1 (Men: n=826 ; n'=1319; Women: n=1099 ; n'=1817); Hypothesis 2 (Men: n=738; n'=1230; Women: n=964; n'=1678). As hypothesized, a higher level of atherogenic indices was linked to faster increase in depressive symptom scores, particularly depressed affect and interpersonal problems, though this relationship was found only among women. Among men a U-shaped relationship between baseline TC and longitudinal increase in somatic complaints and a direct link between low TC and longitudinal putative improvement in positive affect was found. On excluding statin users among women, low TC was associated with slower increase in depressed affect over time, whereas high TC was associated with faster increase in interpersonal problems. In summary, atherogenic indices were directly linked to faster increase in depressive symptoms among women only. More studies are needed to explain these sex-specific associations.

Indications for caesarean sections at ≥34 weeks among nulliparous women and differential composite maternal and neonatal morbidity.

OBJECTIVE: To compare composite maternal and neonatal morbidities (CMM, CNM) among nulliparous women with primary indications for caesarean section (CS) as acute clinical emergency (group I; ACE), non-reassuring fetal heart rate (group II) and arrest disorder (group III). DESIGN: A multicentre prospective study. SETTING: Nineteen academic centres in the USA, with deliveries in 1999-2002. POPULATION: Nulliparous women (n = 9829) that had CS. METHODS: Nulliparous women undergoing CS for three categories of indications were compared using logistic regression model, adjusted for five variables. MAIN OUTCOME MEASURES: CMM was defined as the presence of any of the following: intrapartum or postpartum transfusion, uterine rupture, hysterectomy, cystotomy, ureteral or bowel injury or death; CNM was defined as the presence of any of the following: umbilical arterial pH <7.00, neonatal seizure, cardiac, hepatic, renal dysfunction, hypoxic ischaemic encephalopathy or neonatal death. RESULTS: The primary reasons for CS were ACE in 1% (group I, n = 114) non-reassuring FHR in 29% (group II; n = 2822) and failed induction/dystocia in the remaining 70% (group III; n = 6893). The overall risks of CMM and CNM were 2.5% (95% confidence intervals, CI, 2.2-2.8%) and 1.9% (95% CI 1.7-2.2), respectively. The risk of CMM was higher in group I than in group II (RR 4.1, 95% CI 3.1, 5.3), and group III (RR 3.2, 95% CI 2.7, 3.7). The risk of CNM was also higher in group I than in group II (RR 2.8, 95% CI 2.3, 3.4) and group III (RR 14.1, 95% CI 10.7, 18.7). CONCLUSIONS: Nulliparous women who have acute clinically emergent caesarean sections are at the highest risks of both composite maternal and neonatal morbidity and mortality.

Thyroid hormones are associated with cognitive function: moderation by sex, race, and depressive symptoms.

CONTEXT: Recent evidence indicates that thyroid hormones may be closely linked to cognition among adults. OBJECTIVE: We investigated associations between thyroid hormones and cognitive performance, while testing effect modification by sex, race, and elevated depressive symptoms (EDS). DESIGN: This cross-sectional study used extensive data from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study. SETTING: The study was conducted in Baltimore, Maryland, from 2004 to 2009. PARTICIPANTS: PARTICIPANTS were U.S. adults aged 30 to 64 years. The sample size ranged from 1275 to 1346. MAIN OUTCOME MEASURES: Outcomes included 13 cognitive test scores spanning domains of learning/memory, language/verbal, attention, visuo-spatial/visuo-construction, psychomotor speed, executive function, and mental status. RESULTS: Within reference ranges and after Bonferroni correction, elevated free thyroxine (fT4) was associated with better performance on tests of visuo-spatial/visuo-construction ability (overall, women, and African Americans) and learning/memory (women and African Americans), whereas a higher total thyroxine (tT4) level was associated with better performance in the domain of psychomotor speed (individuals without EDS) and higher levels of both fT4 and tT4 were linked to better language/verbal test performance among men. In contrast, higher T3(% uptake) was related to better performance on tests of visuo-spatial/visuo-construction ability and psychomotor speed among whites. When the above reference range was compared within the overall population and after Bonferroni correction, a within reference range fT4 was linked to better performance on visuo-spatial/visuo-constrution ability and psychomotor speed, whereas a below normal range TSH level (compared with the reference range) was linked to better performance in domains of psychomotor speed and attention. CONCLUSIONS: Thyroid hormones and cognition are closely linked differentially by sex, race, and EDS status.

Associations among 25-hydroxyvitamin D, diet quality, and metabolic disturbance differ by adiposity in adults in the United States.

CONTEXT: Recent evidence indicates that a higher plasma level of 25-hydroxyvitamin D [25(OH)D] is associated with lower adiposity and a reduced number of metabolic disturbances (MetD). OBJECTIVES: We examined associations among dietary quality, 25(OH)D, percent body fat (%BF), and MetD, and a pathway linking them, across central obesity. DESIGN: This cross-sectional nationally representative study used extensive data from the National Health and Nutrition Examination Surveys of 2001-2004. PARTICIPANTS: U.S. adults aged at least 20 yr were stratified by central obesity (CO) status. Sample sizes ranged from 1943 (all MetD combined) to 7796 (each component). MAIN OUTCOME MEASURES: %BF was measured using dual-energy x-ray absorptiometry, and MetD was measured with individual continuous nonadiposity outcomes (e.g. fasting plasma glucose) and with a composite count index of binary MetD with prespecified cutoff points (Index I). RESULTS: A higher 25(OH)D was associated with better dietary quality, lower %BF, and lower number of MetD. These inverse 25(OH)D-%BF and 25(OH)D-MetD associations (i.e. fasting blood glucose, homeostatic model assessment of insulin resistance, C-reactive protein, and Index I) were significantly stronger among the CO+ group. Finally, the pathway linking the dairy component of the Healthy Eating Index (HEIdairy) to Index I through 25(OH)D and %BF indicated complete mediation among the CO- group, but HEIdairy and 25(OH)D had direct inverse associations with Index I among the CO+ group. CONCLUSIONS: Due to potential genetic differences between CO- and CO+ groups, empowering U.S. adults with central obesity to make related behavioral changes may be especially effective in improving their vitamin D status and metabolic profile.

Obesity and central obesity as risk factors for incident dementia and its subtypes: a systematic review and meta-analysis.

While dementia affects 6-10% of persons 65 years or older, industrialized countries have witnessed an alarming rise in obesity. However, obesity's influence on dementia remains poorly understood. We conducted a systematic review and meta-analysis. PUBMED search (1995-2007) resulted in 10 relevant prospective cohort studies of older adults (40-80 years at baseline) with end points being dementia and predictors including adiposity measures, such as body mass index (BMI) and waist circumference (WC). There was a significant U-shaped association between BMI and dementia (P = 0.034), with dementia risk increased for obesity and underweight. Pooled odds ratios (OR) and 95% confidence intervals (CI) for underweight, overweight and obesity compared with normal weight in relation to incident dementia were: 1.36 (1.07, 1.73), 0.88 (0.60, 1.27) and 1.42 (0.93, 2.18) respectively. Pooled ORs and 95% CI for obesity and incident Alzheimer's disease (AD) and vascular dementia were 1.80 (1.00, 3.29) vs. 1.73 (0.47, 6.31) and were stronger in studies with long follow-up (>10 years) and young baseline age (<60 years). Weight gain and high WC or skin-fold thickness increased risks of dementia in all included studies. The meta-analysis shows a moderate association between obesity and the risks for dementia and AD. Future studies are needed to understand optimal weight and biological mechanisms.

Association of human leucocyte antigen sharing with recurrent spontaneous abortions.

An estimated 15% of clinically recognized pregnancies abort spontaneously. Recurrent spontaneous abortion (RSA) is defined as three or more consecutive miscarriages conceived with the same partner in the absence of uterine, genetic or autoimmune abnormalities. Evidence points to human leucocyte antigens (HLA) as playing a role in the successful development of the foetus. In particular, HLA compatibility is more prevalent in couples experiencing reproductive failure, especially RSA couples, compared to fertile couples. According to the immunological hypothesis, an adequate immune response is necessary for proper implantation of the embryo; conversely, a depressed response of maternal lymphocytes to the stimulation by paternal antigens because of HLA sharing can result in disorders, such as RSA. The genetic hypothesis implicates homozygosity for recessive lethal alleles in linkage disequilibrium with specific HLA haplotypes. The specificity of HLA alleles or haplotypes responsible for or linked to other RSA susceptibility genes remains unclear. In this study, we identified 40 observational studies (32 case-control, five cohort, one cross-sectional, one case series and one basic science) that examined the associations between HLA and RSA, focusing on HLA allele couple and maternal-foetal sharing, and the special role of HLA-G. We sought to identify consistent findings among studies examining similar questions. Evidence remains divided concerning the role of HLA allele couple sharing. Of major concern is the focus of many studies on couple sharing as a proxy measure of maternal-foetal sharing. Therefore, adequately powered studies are needed, which employ standard case definitions and reproducible methodologies to directly assess the role of maternal-foetal HLA sharing on the risk of RSA.

Household crowding index: a correlate of socioeconomic status and inter-pregnancy spacing in an urban setting.

OBJECTIVES: This paper examines the effect of household crowding on inter-pregnancy spacing and its association with socioeconomic indicators, among parous mothers delivered in an urban environment. DESIGN: Cross sectional survey. METHODS: Sociodemographic data were obtained on 2466 parous women delivering at eight hospitals in Greater Beirut over a one year period. Statistical methodology comprised Pearson chi(2) test and logistic regression analysis. MAIN RESULTS: A significant inverse relation was observed between household crowding and socioeconomic status, defined as education and occupation of women and their spouses. Inter-pregnancy spacing increased with higher levels of crowding. Further analysis suggested that this positive association was confounded by maternal demographic characteristics. CONCLUSIONS: These data have shown that household crowding, a correlate of low parental socioeconomic status, is associated with longer birth intervals. This association, however, seems to be largely explained by maternal age and parity.

Low socioeconomic status and neonatal outcomes in an urban population in a developing country.

OBJECTIVE: To investigate the effect of low socioeconomic status indicators, specifically parental educational and occupational characteristics on neonatal health outcomes. METHODS: Analysis of 3372 newborn infants admitted to five National Collaborative Perinatal Neonatal Network centers (1 February 2000 to 31 January 2002). Outcomes included birth weight, gestational age, admission to the neonatal intensive care unit (NICU) and length of hospital stay. The independent effects of mother's education and occupation as well as father's occupation on health outcomes were assessed by means of stepwise logistic regression analysis. RESULTS: A total of 271 (8.0%) infants were of low birth weight, 306 (9.1%) were preterm, 410 (12.2%) had NICU admissions and 240 (7.1%) were hospitalized for more than a week. After adjusting for maternal gravidity, age, smoking during pregnancy and pregnancy-related complications, parental socioeconomic characteristics had no significant impact on low birth weight or preterm birth. NICU admission and prolonged hospitalization were significantly correlated with skilled, semi-skilled and unskilled paternal occupations. Illiterate mothers had nearly 3-5 times the risk of NICU admission and prolonged hospitalization. CONCLUSION: Both father's occupation and mother's education play an important role as determinants of neonatal morbidity characteristics.

Is coronary angioplasty safe in the elderly?

OBJECTIVE: To evaluate the use of percutaneous transluminal coronary angioplasty (PTCA) and the immediate procedural outcomes in the elderly at a tertiary care centre. PATIENTS AND METHODS: Between January 1992 and December 1997, a total retrospective cohort study of 2322 consecutive patients aged 60 years or older underwent PTCA. Patients were categorized into three age groups: group A (60 to 69 years of age), which included 1294 patients; group B (70 to 79 years), which included 895 patients; and group C (80 years of age or older), which included 133 patients. PTCA was performed using the newest catheter technology as it became available. RESULTS: Men comprised 63% of the patients in groups A and B combined, and 44% of group C (P<0.001). Canadian Cardiovascular Society angina class IV was present in 45% of group C compared with 30% and 35% in groups A and B, respectively (P<0.001). The proportion of patients with diabetes mellitus and hypertension was similar among the three groups. Acute myocardial infarction before PTCA was twice as common at 4.5% (95% CI 3.7% to 5.3%) in group C, compared with 2.9% (95% CI 2.7% to 3.1%) and 2.2% (95% CI 2.0% to 2.3%) in groups A and B, respectively. The procedural success rate was similar at 93%, 92.7% and 91.7% in groups A, B and C, respectively. A total of five (0.2%) deaths and eight (0.34%) myocardial infarctions occurred in groups A and B combined, while none occurred in group C (not significant). More patients in groups A and B underwent emergency coronary artery bypass graft than in group C: group A - 22, 3.4% (95% CI 3.2% to 3.6%); group B - 16, 3.4% (95% CI 3.2% to 3.6%) and group C - one, 0.75% (95% CI 0.6% to 0.9%). CONCLUSIONS: In this retrospective series of patients, it was shown that PTCA may be performed in the very elderly with high procedural success and acceptable risk. Age alone should not be the criterion to limit the use of PTCA.