Attenuation Statistics Research Articles

Second order experimental statistics of rain attenuation at Ka band in a tropical location

Abstract Some second order rain attenuation statistics such as fade duration and fade slope are investigated on the basis of experimental measurements of received signals using the GSAT-14 satellite beacon signal at 20.2 GHz for three years (2014–2016) over the tropical location Ahmedabad (23.02 0E, 72.510N), India with an Elevation angle of 630. Existing models of fade duration are compared with experimental data in this study and exponent of power law model of fade duration at Ka band is further explored. A new model for fade duration for Ka band for tropical locations is proposed where the constant of exponent of attenuation in the power law is found to be 0.143 instead of 0.055 used in ITU-R. Other relevant parameters for implementation of fade mitigation technique to prevent the link outage like cumulative distribution of signal fade rate, maximum and minimum fade rise and fade fall are also studied. Fade slope asymmetry over tropical region is also investigated. Keeping in view of exploiting the commercial launch of Ka band in Indian region there is an urgent need for validation of the existing models of fade slope (specially looking into fade symmetry) and fade duration. It will help the SATCOM (Satellite Communication) link designer to improve closed loop fade mitigation technique to minimize the possible link failure/link outage over the tropical region.

A Time Diversity Model for EHF Satellite Communication Systems

A simple yet effective time diversity model, referred to as Time Diversity Stratiform Convective EXCELL (TD-SCEX), is presented. The model, conceived to support the design of EHF Earth-space communication systems implementing Fade Mitigation Techniques, takes advantage of the Stratiform Convective EXponential CELL (SC EXCELL) model to predict the joint rain attenuation statistics and, hence, the time diversity gain, starting from the geometrical and electrical characteristics of the link, as well as from the joint rain rate statistics. The model performance is evaluated against the data collected in Milan, Madrid, and Spino d'Adda at Ka-, Q-, and V-bands in the framework of different long-term propagation campaigns. Results indicate that TD-SCEX is a useful tool to predict the effectiveness of time diversity in improving the performance of EHF Earth-space communication systems.

Improving bayesian posterior correlation analysis on type Ia supernova luminosity evolution

ABSTRACT Much of the cosmological utility thus far extracted from Type Ia supernovae (SNe Ia) relies on the assumption that SN Ia peak luminosities do not evolve significantly with the age (local or global) of their stellar environments. Two recent studies have provided conflicting results in evaluating the validity of this assumption, with one finding no correlation between Hubble residuals (HR) and stellar environment age, while the other claims a significant correlation. In this Letter we perform an independent reanalysis that rectifies issues with the statistical methods employed by both of the aforementioned studies. Our analysis follows a principled approach that properly accounts for regression dilution and critically (and unlike both prior studies) utilizes the Bayesian-model-produced SN environment age estimates (posterior samples) instead of point estimates. Moreover, the posterior is used as an informative prior in the regression. We find the Pearson correlation between the HR and local (global) age to be in excess of 4σ (3σ). Assuming there exists a linear relationship between HR and local (global) age, we find a corresponding slope of −0.035 ± 0.007 mag Gyr−1 (−0.036 ± 0.007 mag Gyr−1). We encourage further use of our approach to examine HR and host environment correlations, as well as experiments in correcting for luminosity evolution in SN Ia standardization.

Financial Literacy and the Perceived Value of Stress Testing: An Experiment Using Students in Brazil

ABSTRACT We run an experiment to test how consumers of banking services value stress tests performed by their banks. We query respondents about the extent to which they would be willing to trade profitability if banks conduct stress tests, maybe for greater bank financial stability. Our paper connects and innovates in the banking literature by providing empirical evidence of the value of communicating bank stress tests routines to the public from the consumer perspective rather than the regulator’s usual perspective or of the bank itself. By performing stress tests and communicating them to their customers, we find that consumers accept lower remuneration rates of their deposits, suggesting they value stress testing. Our experimental design also contains several queries to estimate the degree of financial literacy of respondents. By combining both perspectives, we find that respondents with higher financial literacy levels are more conservative and replace more profitable banks with less profitable banks that perform and communicate stress testing routines to the public. We explicitly consider measurement error in our data collection process of respondents’ rather subjective financial literacy indicator by introducing external instruments. Such consideration aims at mitigating attenuation bias. We also run several robustness tests with subsets of our sample and non-linear models, such as Probit.

Cloud Attenuation Statistical Model for Satellite-Based FSO Communications

This letter addresses the attenuation statistics due to the clouds on satellite-based free-space optical communications. Specifically, we present a novel distribution model of monthly cloud attenuation for several regions in Japan. To this purpose, a five-year reanalysis meteorological database, namely, ERA-Interim, produced from the European Center for Medium-Range Weather Forecast (ECMWF), is investigated. The cloud liquid water content (CLWC) obtained from the ECMWF ERA-interim database is used to determine the cloud attenuation. The curve-fitting method is performed to derive the probability density function (PDF) of cloud attenuation. The results show that the log-normal distribution best models the PDF of monthly cloud attenuation.

Association between blood pressure and BMI with bladder cancer risk and mortality in 340,000 men in three Swedish cohorts.

BackgroundThe relation between obesity, blood pressure (BP) and bladder cancer (BC) risk and mortality remains unclear, partially due to potential confounding by smoking, the strongest risk factor for BC, and not accounting for tumor stage and grade in such studies. We investigated body mass index (BMI) and BP in relation to BC risk by stage and grade, and BC‐specific mortality, including separately among never‐smokers aimed at minimizing confounding by smoking.MethodsWe analyzed 338,910 men from three Swedish cohorts, with 4895 incident BC's (940 among never‐smokers) during follow‐up. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals adjusted for smoking status. HRs for BMI and BP were corrected for their regression dilution ratios, calculated from 280,456 individuals with 758,641 observations.ResultsBody mass index was positively associated with non‐muscle invasive BC (NMIBC, HR per 5 kg/m2, 1.10 [1.02–1.19]) and NMIBC grade 3 (HR 1.17 [1.01–1.34]) in the full cohort, with similar effect sizes, albeit non‐significant, among never‐smokers. Systolic BP was positively associated with muscle‐invasive BC (MIBC, HR per 10 mmHg, 1.25 [1.00–1.55]) and BC‐specific mortality (HR 1.10 [1.01–1.20]) among never‐smokers, with weaker and non‐significant associations in the full cohort.ConclusionsIn an analyses of BMI, BP and BC risk by stage and grade among men, we found modest positive associations between BMI and NMIBC and NMIBC grade 3. SBP was positively associated with MIBC and BC‐specific mortality in an analysis of never‐smokers, which may reflect the association, un‐confounded by smoking, also in a broader population.

Using Machine Learning to Measure Conservatism

Using a neural network, we develop novel measures of conservatism that fits non-linearities and interactions absent in prior literature. The machine-learning measures exhibit (i) fewer economically anomalous observations, (ii) economic associations consistent with existing studies, (iii) less unexplained year-over-year instability, and (iv) higher economic magnitudes consistent with reduced attenuation bias. The measure further reveals intuitive trends toward a secular decline in conservatism in the US. In simulations, linear models perform honorably even in the presence of a complex data-generating process but causal inference based on machine learning is the most robust to misspecification. The approach offers the promise of reducing noise in measurements and design more powerful tests to assess theories of conservatism.

Circulating insulin-like growth factor-I, total and free testosterone concentrations and prostate cancer risk in 200 000 men in UK Biobank.

Insulin‐like growth factor‐I (IGF‐I) and testosterone have been implicated in prostate cancer aetiology. Using data from a large prospective full‐cohort with standardised assays and repeat blood measurements, and genetic data from an international consortium, we investigated the associations of circulating IGF‐I, sex hormone‐binding globulin (SHBG), and total and calculated free testosterone concentrations with prostate cancer incidence and mortality. For prospective analyses, risk was estimated using multivariable‐adjusted Cox regression in 199 698 male UK Biobank participants. Hazard ratios (HRs) were corrected for regression dilution bias using repeat hormone measurements from a subsample. Two‐sample Mendelian randomisation (MR) analysis of IGF‐I and risk used genetic instruments identified from UK Biobank men and genetic outcome data from the PRACTICAL consortium (79 148 cases and 61 106 controls). We used cis‐ and all (cis and trans) SNP MR approaches. A total of 5402 men were diagnosed with and 295 died from prostate cancer (mean follow‐up 6.9 years). Higher circulating IGF‐I was associated with elevated prostate cancer diagnosis (HR per 5 nmol/L increment = 1.09, 95% CI 1.05‐1.12) and mortality (HR per 5 nmol/L increment = 1.15, 1.02‐1.29). MR analyses also supported the role of IGF‐I in prostate cancer diagnosis (cis‐MR odds ratio per 5 nmol/L increment = 1.34, 1.07‐1.68). In observational analyses, higher free testosterone was associated with a higher risk of prostate cancer (HR per 50 pmol/L increment = 1.10, 1.05‐1.15). Higher SHBG was associated with a lower risk (HR per 10 nmol/L increment = 0.95, 0.94‐0.97), neither was associated with prostate cancer mortality. Total testosterone was not associated with prostate cancer. These findings implicate IGF‐I and free testosterone in prostate cancer development and/or progression.

Reliability of Office, Home, and Ambulatory Blood Pressure Measurements and Correlation With Left Ventricular Mass

BackgroundDetermining the reliability and predictive validity of office blood pressure (OBP), ambulatory BP (ABP), and home BP (HBP) can inform which is best for diagnosing hypertension and estimating risk of cardiovascular disease. ObjectivesThis study aimed to assess the reliability of OBP, HBP, and ABP and evaluate their associations with left ventricular mass index (LVMI) in untreated persons. MethodsThe Improving the Detection of Hypertension (IDH) study, a community-based observational study, enrolled 408 participants who had OBP assessed at 3 visits, and completed 3 weeks of HBP, 2 24-h ABP recordings, and a 2-dimensional echocardiogram. Mean age was 41.2 ± 13.1 years, 59.5% were women, 25.5% African American, and 64.0% Hispanic. ResultsThe reliability of 1 week of HBP, 3 office visits with mercury sphygmomanometry, and 24-h ABP were 0.938, 0.894, and 0.846 for systolic and 0.918, 0.847, and 0.843 for diastolic BP, respectively. The correlations among OBP, HBP, and ABP, corrected for regression dilution bias, were 0.74 to 0.89. After multivariable adjustment including OBP and 24-h ABP, 10 mm Hg higher systolic and diastolic HBP were associated with 5.07 (standard error [SE]: 1.48) and 3.92 (SE: 2.14) g/m2 higher LVMI, respectively. After adjustment for HBP, neither systolic or diastolic OBP nor ABP was associated with LVMI. ConclusionsOBP, HBP, and ABP assess somewhat distinct parameters. Compared with OBP (3 visits) or 24-h ABP, systolic and diastolic HBP (1 week) were more reliable and more strongly associated with LVMI. These data suggest that 1 week of HBP monitoring may be the best approach for diagnosing hypertension.

Is there an Attenuation Bias in the Effect of Economic Policy Uncertainty? Historical Evidence from the U.S.

A large and growing literature investigates the effects of economic policy uncertainty on various measures of economic activity. Virtually all of it concentrates on the modern era. We show that estimates based on post-WWII data likely suffer from an attenuation bias because the modern-period systematic government reaction function induces anticipation to policy intervention during periods of economic uncertainty. Using pre-1913 data, when active fiscal and monetary policy as well as the anticipation of intervention were absent, we find that the EPU effect on output to be four to six times larger relative to the effect measured with modern data.

Effects of within-person variability in spot urinary sodium measurements on the associations with blood pressure and risk of cardiovascular disease in 0.5 Million adults in UK Biobank

Abstract Background Randomised control trials have demonstrated direct positive and causal associations of 24-hr measurements of urinary sodium excretion on blood pressure. However, prospective studies, which often used spot (not 24-hr) measurements of urinary sodium, have reported J-shaped associations with higher risks of cardiovascular disease (CVD) at sodium intake <4 g/day. The reasons for the discrepant results are not fully understood, but have prompted some to question the World Health Organisation's recommendations to restrict sodium intake to <2.3g/day. Purpose We examined the effects of within-person variability in spot urinary sodium (UNa) measurements on immediate and delayed associations of UNa with blood pressure at baseline and at resurvey, and with incident cardiovascular disease in the UK Biobank (UKB). Methods Baseline spot urine samples were measured in 502,619 adults at baseline and in 20,346 participants who were resurveyed at 4 years after baseline. Linear regression was used to assess associations of baseline UNa measurements with systolic blood pressure (SBP; mmHg) at baseline and at resurvey. Cox regression was used estimate the associations between baseline measures of UNa with incident CVD events (recorded from linkage with hospital records). All analyses were adjusted for confounders and corrected for regression dilution bias. Results After excluding participants with prevalent diseases, the primary analyses involved 386,060 adults who were followed-up for a median of 7.8 years, during which ∼13,000 CVD events occurred. Estimated mean (SD) urinary sodium excretion was 77.4 mmol/L (SD 44.4, IQR = 42.8–103.7 mmol/L), and mean SBP/DBP were 137.5/82.3 (SD 18.5/10.1) mmHg, respectively. Within-person variability in UNa was high, with a self-correlation of 0.35 at 4 years between measurements. After adjustment for confounders and correction for regression dilution bias, a 100 mmol/L higher UNa was associated with an immediate 3.2 mmHg higher SBP (95% confidence interval [CI]: 2.8–3.6) in cross-sectional analyses (Figure 1). However, the corresponding associations of baseline UNa with SBP at resurvey was completely attenuated (p=0.20). The predicted risk of CVD was 1.06 (95% CI 1.06–1.07, p<0.001) for a 3.2 mmHg higher SBP, but the observed risk for a 100 mmol/L higher UNa was 0.95 (95% CI 0.82–1.10, p=0.47) (Figure 1). Conclusions While spot measurements of UNa were strongly associated with immediate effects on SBP, the magnitude of within-person variability in UNa precluded detection of associations with SBP several years after baseline or with risk of CVD. The extreme within-person variability in spot UNa may explain the discrepant results of the trials and observational studies of sodium and blood pressure. Figure 1. Spot UNa with SBP and CVD in UK Biobank Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Core funding from the Medical Research Council-Population Health Research Unit, British Heart Foundation

Further Evidence for Significant Luminosity Evolution in Supernova Cosmology

Abstract Supernova (SN) cosmology is based on the assumption that the corrected luminosity of SNe Ia would not evolve with redshift. Recently, our age dating of stellar populations in early-type host galaxies (ETGs) from high-quality spectra has shown that this key assumption is most likely in error. It has been argued though that the age–Hubble residual (HR) correlation from ETGs is not confirmed from two independent age data sets measured from multiband optical photometry of host galaxies of all morphological types. Here we show, however, that one of the data sets is based on highly uncertain and inappropriate luminosity-weighted ages derived, in many cases, under serious template mismatch. The other data set employs more reliable mass-weighted ages, but the statistical analysis involved is affected by regression dilution bias, severely underestimating both the slope and significance of the age–HR correlation. Remarkably, when we apply regression analysis with a standard posterior sampling method to this data set comprising a large sample (N = 102) of host galaxies, very significant (>99.99%) correlation is obtained between the global population age and HR with the slope (−0.047 ± 0.011 mag Gyr−1) highly consistent with our previous spectroscopic result from ETGs. For the local age of the environment around the site of SNe, a similarly significant (>99.96%) correlation is obtained with a steeper slope (−0.057 ± 0.016 mag Gyr−1). Therefore, the SN luminosity evolution is strongly supported by the age dating based on multiband optical photometry and can be a serious systematic bias in SN cosmology.

Robust methods to correct for measurement error when evaluating a surrogate marker.

The identification of valid surrogate markers of disease or disease progression has the potential to decrease the length and costs of future studies. Most available methods that assess the value of a surrogate marker ignore the fact that surrogates are often measured with error. Failing to adjust for measurement error can erroneously identify a useful surrogate marker as not useful or vice versa. We investigate and propose robust methods to correct for the effect of measurement error when evaluating a surrogate marker using multiple estimators developed for parametric and nonparametric estimates of the proportion of treatment effect explained by the surrogate marker. In addition, we quantify the attenuation bias induced by measurement error and develop inference procedures to allow for variance and confidence interval estimation. Through a simulation study, we show that our proposed estimators correct for measurement error in the surrogate marker and that our inference procedures perform well in finite samples. We illustrate these methods by examining a potential surrogate marker that is measured with error, hemoglobin A1c, using data from the Diabetes Prevention Program clinicaltrial.

Cloud attenuation statistics from radiometric measurements over a tropical location Kolkata, India

The objective of this study is to investigate cloud attenuation at 30 GHz frequency using ground-based microwave radiometric observations at a tropical location, Kolkata. At higher frequencies and lower elevation angles, cloud attenuation is of major concern at a tropical location. The location experiences high value of liquid water path (LWP), which is responsible for cloud attenuation, during the Indian summer monsoon (ISM) and pre-monsoon season. Significant amount of cloud attenuation has been observed during monsoon season at 30 GHz. Two years observations of exceedance probability of cloud attenuation and worst month statistics are presented. The variation of cloud attenuation with frequencies for different elevation angles has also been investigated. The seasonal and diurnal patterns of cloud attenuation are examined. Cloud attenuation, inferred from radiometric measurements before rain commencement, has been compared to rain attenuation at Ku-band. Exceedance probabilities of cloud and rain attenuation have been compared.

Physical activity may not be associated with long-term risk of dementia and Alzheimer's disease.

BackgroundWhile it is well established that physical activity is associated with reduced risk of vascular and nonvascular outcomes as well as mortality, evidence on the association between physical activity and dementia is inconsistent. We aimed to assess the associations of physical activity with the risk of dementia and Alzheimer's disease (AD).Material and methodsWe analysed data on 2394 apparently healthy men with good baseline cognitive function from the prospective population‐based Kuopio Ischaemic Heart Disease study. We assessed habits of physical activity at baseline using a 12‐month leisure time physical activity (LTPA) questionnaire. Using Cox regression, we calculated hazard ratios adjusted for body mass index, systolic blood pressure, smoking status, history of type‐2 diabetes, total cholesterol, high‐density lipoprotein cholesterol, alcohol consumption, history of coronary heart disease and high‐sensitivity C‐reactive protein.ResultsDuring a median follow‐up of 24.9 years (interquartile range: 18.3‐26.9), 208 men developed dementia and 128 developed AD. Multivariable adjusted hazard ratios for dementia comparing top vs bottom tertiles of physical activity were 0.97 (95% confidence intervals: 0.69‐1.38) for total physical activity volume, 0.96 (0.69‐1.34) for conditioning LTPA volume and 1.13 (0.80‐1.61) for total LTPA volume. Corresponding hazard ratios for AD were 1.19 (0.76‐1.85), 0.98 (0.64‐1.49) and 1.22 (0.77‐1.93). Associations were consistent in analyses restricted to participants with ≥10 years of follow‐up.ConclusionsIn middle‐aged Caucasian men, various physical activity exposures were not associated with all‐cause dementia or AD. Future studies should address biases due to reverse causation and regression dilution and should involve objective measures of physical activity.

Impact of residential mobility on estimated environmental exposures in a prospective cohort of older women.

We evaluated residential mobility in the Iowa Women's Health Study (age 55-69 years) over 19 years of follow-up (1986-2004). We assessed several environmental exposures of varying spatial scales at enrollment and follow-up addresses. Exposures included average nitrate concentrations in public water supplies, percent of agricultural land (row crops and pasture/hay) within 750 m, and the presence of concentrated animal feeding operations within 5 km. In comparison to gold standard duration-based exposures averaged across all residences, we evaluated the sensitivity and specificity of exposure metrics and attenuation bias for a hypothetical nested case-control study of cancer, which assumed participants did not move from their enrollment residence. Among 41,650 participants, 32% moved at least once during follow-up. Mobility was predicted by working outside the home, being a former/current smoker, having a higher education level, using a public drinking water supply, and town size of previous residence. Compared with duration-based exposures, the sensitivity and specificity of exposures at enrollment ranged from 94% to 99% and 97% to 99%, respectively. A hypothetical true odds ratio of 2.0 was attenuated 8% for nitrate, 9%-10% for agricultural land, and 6% for concentrated animal feeding operation exposures. Overall, we found low rates of mobility and mobility-related exposure misclassification in the Iowa Women's Health Study. Misclassification and attenuation of hypothetical risk estimates differed by spatial variability and exposure prevalence.

Twenty-Four–Hour Urinary Sodium and Potassium Excretion and Their Associations With Blood Pressure Among Adults in China

This study aimed to assess current level of sodium and potassium intake and their associations with blood pressure (BP) using the 24-hour urinary data in a large sample of China. Data from participants aged 18 to 75 years were collected as the baseline survey of Action on Salt China in 2018. Of 5454 adults, 5353 completed 24-hour urine collection. The average sodium, potassium excretion, and sodium-to-potassium molar ratio were 4318.1±1814.1 mg/d (equivalent to 11.0±4.6 g/d of salt), 1573.7±627.1 mg/d, and 5.0±2.1, respectively. After adjusting for potential confounding factors and correcting for regression dilution, each 1000-mg increase in sodium excretion was associated with increased systolic BP (1.32 mm Hg [95% CI, 0.92-1.81]) and diastolic BP (0.34 mm Hg [95% CI, 0.09-0.60]). Each 1000-mg increase in potassium excretion was inversely associated with systolic BP (-3.19 mm Hg [95% CI, -4.38 to -2.20]) and diastolic BP (-1.56 mm Hg [95% CI, -2.29 to -0.90]). Each unit increase in sodium-to-potassium molar ratio was associated with an increase of systolic BP by 1.21 mm Hg (95% CI, 0.91-1.60) and diastolic BP by 0.44 mm Hg (95% CI, 0.24-0.64). The relationships between sodium and BP mostly increase with the rise of BP quantiles. Potassium shows the opposite trend. The current sodium intake in Chinese adults remains high and potassium intake is low. Sodium and sodium-to-potassium ratio were positively associated with BP, whereas potassium was inversely associated with BP. Registration- URL: https://tinyurl.com/vdr8rpr; Unique identifier: ChiCTR1800017553. URL: https://tinyurl.com/w8c7x3w; Unique identifier: ChiCTR1800016804. URL: https://tinyurl.com/s3ajldw; Unique identifier: ChiCTR1800018119.

Examination of potential novel biochemical factors in relation to prostate cancer incidence and mortality in UK Biobank

BackgroundAlthough prostate cancer is a leading cause of cancer death, its aetiology is not well understood. We aimed to identify novel biochemical factors for prostate cancer incidence and mortality in UK Biobank.MethodsA range of cardiovascular, bone, joint, diabetes, renal and liver-related biomarkers were measured in baseline blood samples collected from up to 211,754 men at recruitment and in a subsample 5 years later. Participants were followed-up via linkage to health administrative datasets to identify prostate cancer cases. Hazard ratios (HRs) and 95% confidence intervals were calculated using multivariable-adjusted Cox regression corrected for regression dilution bias. Multiple testing was accounted for by using a false discovery rate controlling procedure.ResultsAfter an average follow-up of 6.9 years, 5763 prostate cancer cases and 331 prostate cancer deaths were ascertained. Prostate cancer incidence was positively associated with circulating vitamin D, urea and phosphate concentrations and inversely associated with glucose, total protein and aspartate aminotransferase. Phosphate and cystatin-C were the only biomarkers positively and inversely, respectively, associated with risk in analyses excluding the first 4 years of follow-up. There was little evidence of associations with prostate cancer death.ConclusionWe found novel associations of several biomarkers with prostate cancer incidence. Future research will examine associations by tumour characteristics.

Associations between usual glycated haemoglobin and cardiovascular disease in patients with type 2 diabetes mellitus: A 10-year diabetes cohort study.

To investigate the assocation between glycated haemoglobin (HbA1c) level and cardiovascular disease (CVD) risk among patients with type 2 diabetes. This retrospective cohort study conducted in Hong Kong selected patients aged 45 to 84 years with type 2 diabetes mellitus and without CVD from primary care clinics during the period 2008 to 2010. Usual HbA1c measurement was calculated using a mixed-effects model to minimize regression dilution bias. The association between usual HbA1c and CVD risk was assessed by Cox regression, with adjustment for baseline covariates. Subgroup analyses by patient characteristics were also conducted. After a median follow-up period of 8.4 years (1.4 million person-years), 174 028 patients with 34 074 CVD events were observed. A curvilinear association was found between usual HbA1c and total CVD, stroke, heart failure and CVD mortality risk. No significant difference was found among patients with usual HbA1c <53 mmol/mol (7%). A positive linear association was found between usual HbA1c and the risks of outcomes when the usual HbA1c was 53 mmol/mol (7%) or above. The adjusted hazard ratios (HRs) for CVD risk per 1% increment in usual HbA1c >7% was 21% (HR 1.21, 95% confidence interval [CI] 1.18-1.23) (HR for CVD per 1mmol/mol increment in usual HbA1c > 53 mmol/mol was 1.7% (HR 1.017, CI 1.015-1.019)). A similar pattern was identified in a patient subgroup analysis, but the effects of usual HbA1c in younger patients were more prominent than in older patients. Usual HbA1c increments for levels >53 mmol/mol (7.0%) were associated with elevated CVD risk, but no difference was found in the population with usual HbA1c <53 mmol/mol (7.0%), irrespective of patient characteristics. For CVD prevention, strict adherence to an HbA1c target of <53 mmol/mol (7%) should apply to younger patients.

Circulating Insulin-like Growth Factor-I Concentrations and Risk of 30 Cancers: Prospective Analyses in UK Biobank.

Circulating insulin-like growth factor I (IGF-I) is positively associated with the risks of colorectal, breast, and prostate cancer, but evidence for other less common cancers is limited. In this study, we investigated associations between serum IGF-I concentrations and incidence of less common cancers in the UK Biobank study. To enable comparison of effect estimates, and as positive controls, both common and less common cancer sites (total 30) were included in an outcome-wide analysis. Data from 394,388 cancer-free participants in the UK Biobank study were analyzed. Multivariable adjusted Cox proportional hazards models were used to determine associations between baseline serum IGF-I concentrations and cancer incidence, using repeated IGF-I measurements from up to 14,149 participants to correct for regression dilution bias. Higher IGF-I concentration was associated with increased risks of thyroid cancer [HR per 5 nmol/L higher concentration 1.18; 95% confidence interval (CI), 1.01-1.37] in addition to colorectal (HR, 1.08; 95% CI, 1.03-1.13), breast (HR, 1.11; 95% CI, 1.07-1.15), and prostate cancer (HR, 1.08; 95% CI, 1.05-1.12), and reduced risks of ovarian and liver cancer. Mean follow-up was 6.9 years and the possibility that the observed associations may be influenced by reverse causality bias cannot be excluded. Additional nominally significant associations with malignant melanoma, multiple myeloma, oral cancer, and esophageal squamous cell carcinoma did not survive correction for multiple testing. Studies with longer follow-up and pooled analyses are needed to further assess how broad the role of IGF-I is in cancer development. SIGNIFICANCE: The results from this outcome-wide analysis are consistent with a positive association of IGF-I with cancers at several sites.