Log-linear Fashion Research Articles

Association Between Magnitude of Differential Blood Pressure Reduction and Secondary Stroke Prevention

The degree to which more intensive blood pressure reduction is better than less intensive for secondary stroke prevention has not been delineated. To perform a standard meta-analysis and a meta-regression of randomized clinical trials to evaluate the association of magnitude of differential blood pressure reduction and recurrent stroke in patients with stroke or transient ischemic attack (TIA). PubMed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov were searched from January 1, 1980, to June 30, 2022. Randomized clinical trials that compared more intensive vs less intensive blood pressure lowering and recorded the outcome of recurrent stroke in patients with stroke or TIA. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was used for abstracting data and assessing data quality and validity. Risk ratio (RR) with 95% CI was used as a measure of the association of more intensive vs less intensive blood pressure lowering with primary and secondary outcomes. The univariate meta-regression analyses were conducted to evaluate a possible moderating effect of magnitude of differential systolic blood pressure (SBP) and diastolic blood pressure (DBP) reduction on the recurrent stroke and major cardiovascular events. The primary outcome was recurrent stroke and the lead secondary outcome was major cardiovascular events. Ten randomized clinical trials comprising 40 710 patients (13 752 women [34%]; mean age, 65 years) with stroke or TIA were included for analysis. The mean duration of follow-up was 2.8 years (range, 1-4 years). Pooled results showed that more intensive treatment compared with less intensive was associated with a reduced risk of recurrent stroke in patients with stroke or TIA (absolute risk, 8.4% vs 10.1%; RR, 0.83; 95% CI, 0.78-0.88). Meta-regression showed that the magnitude of differential SBP and DBP reduction was associated with a lower risk of recurrent stroke in patients with stroke or TIA in a log-linear fashion (SBP: regression slope, -0.06; 95% CI, -0.08 to -0.03; DBP: regression slope, -0.17; 95% CI, -0.26 to -0.08). Similar results were found in the association between differential blood pressure lowering and major cardiovascular events. More intensive blood pressure-lowering therapy might be associated with a reduced risk of recurrent stroke and major cardiovascular events. These results might support the use of more intensive blood pressure reduction for secondary prevention in patients with stroke or TIA.

Convection velocity of temperature fluctuations in a natural convection boundary layer

Measurements of instantaneous temperature are carried out in a natural convection boundary layer (NCBL) developing over a vertical hot plate using a combination of an infra-red sensor, three cold-wire probes and a Resistance Temperature device (RTD). The aim of this study is to establish experimental procedures for high spatial and temporal resolution temperature measurements, and use that information to measure the convective speed of thermal structures in the flow. The evolution of NCBL along the hot plate is compared against existing empirical models. Statistics of mean and fluctuating temperature are in excellent agreement with the previously reported experimental data for a turbulent NCBL. The boundary layer thickness is observed to grow as y0.45, where y is the vertical distance along the heated plate. Separate experiments are conducted by varying the heat input to investigate its effect on convection velocity (Uc) of thermal structures in the flow. It is found that Uc remained nominally constant in the region 0 ≤ x ≤ δT/2 (δT is the thickness of thermal boundary layer) and decreased in a log-linear fashion in the outer region of NCBL. The results of Uc are found to be consistent with the shadowgraph measurements carried out in the same test rig, and the normalised convection velocity, Uc*=UcδTν is found to depend on Rayleigh number as Uc*∝Ra0.82, where ν is the kinematic viscosity of air. Importantly, these experimental observations are in agreement with the three layer model put forth by Wells and Worster (2008).

Prevalence of Hypertension and Risk Factors

Hypertension is a major chronic life style disease and important public health problem worldwide. Hypertension as rule defined by the existence of a chronic altitude of systemic arterial pressure above a certain sill value. However, rising evidence indicates that the cardiovascular (CV) risk associated with elevation of blood pressure (BP) above approximately 115/75mmHg increases in a log-linear fashion. A recent review indicates that nearly one billion adults had hypertension in 2000 and this is predicted to increase to 1.56billion by 2025. The review previous studies were method to take out of recently study. The aim of review article to showing of both classification aspects of hypertension, blood pressure measurement, treatment of hypertension, hypertension in specific circumstances, hypertension and disease and blood pressure relationship with risk factor. In conclusion knowledge and awareness regarding the health consequences of lifestyle changes are generally expected to be high among clinicians. This in turn could influence the prevalence of lifestyle diseases such as diabetes and hypertension among them.

Seasonal and diel patterns in activity and habitat use by brook trout (Salvelinus fontinalis) in a small Newfoundland lake

Despite the challenges winter poses to salmonids inhabiting temperate and northern environments, there are relatively few studies that evaluate the factors that influence activity and habitat use during this season, particularly for lake environments that are ice-covered. This study examines brook trout depth distribution and movement (activity and range) in relation to temperature, light, and time of day across a 17-month period in a small lake in Newfoundland, Canada. Brook trout maintained elevated diurnal activity patterns throughout the year, despite seasonal changes in temperature, shifts in depth use, and prolonged, ice-induced darkness. Despite the tendency for relatively lower activity at night, brook trout remained active nocturnally, inferring a shift in foraging modes rather than a cessation of feeding. Winter movement velocities and ranges were less than other seasons but they occupied littoral areas that overlapped extensively with spring and fall core ranges. In contrast, summer core ranges of brook trout were principally comprised of areas with cooler water in the deep portion of the lake. As water temperature increased, daytime movement velocities increased in a log-linear fashion, whereas modeled nighttime movement velocity relationships with temperature were curvilinear and included the lowest movement velocities at 2–3 °C and the highest at the extremes of the occupied temperature range. The ability of brook trout to maintain diurnal activity patterns throughout a wide spectrum of environmental conditions suggests a strong behavioral and physiological capacity to adapt to their seasonally variable environment.

Prolonged shedding of type 55 human adenovirus in immunocompetent adults with adenoviral respiratory infections.

Human adenovirus (HAdV) is a common pathogen causing respiratory infections with outbreaks reported in the military and community. However, little information is available on the shedding kinetics. We performed a prospective study of immunocompetent adults confirmed with HAdV respiratory infection by multiplex real-time PCR during an outbreak of HAdV-55. Consecutive respiratory specimens of sputum or nasopharyngeal swab were collected from each patient every 2days. Viral load was measured by real-time quantitative PCR. Of 32 enrolled patients, 27 (84.4%) had pneumonia. Five patients (15.6%) received cidofovir. Viral load was highest in the earliest samples at 8.69 log10 copies/mL. In a linear regression model, viral load declined consistently in a log-linear fashion at the rate of - 0.15 log10 copies/mL per day (95% confidence interval (CI): - 0.18, - 0.12; R2 = 0.32). However, the regression model estimated the viral shedding duration to be 55days. The rate of decline in viral load did not differ between patients who received cidofovir and who did not. Patients with prominent respiratory symptoms or extensive involvement on chest radiograph had higher volume of viral excretion. Prolonged viral shedding was observed in otherwise healthy adults with HAdV-55 respiratory infection. This finding should be considered in the establishment of infection control and prevention strategies.

2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.

2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.

Baseline low-density lipoprotein cholesterol to predict the extent of cardiovascular benefit from lipid-lowering therapies: a review.

Lipid-lowering therapies have been shown to improve cardiovascular outcome in a wide range of patients. The current guidelines recommend a graded approach to reduction in low-density lipoprotein cholesterol (LDL-C) proportional to the patient's risk, with the goal of achieving either a certain magnitude of reduction or a specific threshold of final LDL-C. Recent findings from a meta-analysis of numerous randomized trials suggest that more attention should be given to the baseline LDL-C of an individual patient. In this review, we discuss how the baseline LDL-C level may provide a means to better understand the results of recent cardiovascular outcome trials and the expected benefits of lipid-lowering therapies. The exact quantification of the clinical benefit associate with an intensified lipid-lowering therapy depends on the baseline LDL-C. Mortality is reduced in a log-linear fashion only when LDL-C > 100 mg/dL.

Long-term effectiveness of one and two doses of a killed, bivalent, whole-cell oral cholera vaccine in Haiti: an extended case-control study.

SummaryBackgroundNo study of long-term protection following killed oral cholera vaccination has been done outside of the historically cholera-endemic areas of south Asia, or has examined protection after a single-dose vaccination regimen. To address this, we examined the duration of protection of the standard two-dose regimen and an incomplete regimen of one dose up to 4 years after vaccination in Haiti.MethodsIn the setting of two-dose vaccination campaigns with a killed, bivalent, whole-cell oral cholera vaccination, we did a case-control study from October, 2012 through November, 2016. Eligible participants were required to be resident in the vaccine catchment area (Artibonite Department or Central Department) where they were recruited at the start of the study; and be eligible for the vaccination campaign (ie, aged ≥12 months, not pregnant, and living in the region at the time of the vaccine campaign). Patients with cholera had a positive stool culture and were recruited from cholera treatment centres. Community controls were matched to people with cholera by age group, time, and neighbourhood. We did adjusted matched regression analyses to calculate vaccine effectiveness and examine heterogeneity in effectiveness over time. The primary outcome was the effectiveness of one and two oral cholera doses as compared with zero doses from 2 months to 48 months after vaccination, measured by self reporting.FindingsAmong 178 people assigned to the case group and 706 people assigned to the control group, we found no evidence that two-dose effectiveness decreased during follow-up. In adjusted analyses, the average cumulative 4 year effectiveness for two doses was 76% (95% CI 59–86). In contrast, single-dose effectiveness decreased over time in a log-linear fashion, with a predicted vaccine effectiveness of 79% at the end of 12 months (95% CI 43–93), which declined to zero before the end of the second year.InterpretationIn a setting of epidemic and newly endemic cholera in Haiti, single-dose vaccination with killed, bivalent, whole-cell oral cholera vaccination provided short-term protection; however, vaccination with two doses was required for long-term protection, which lasted up to 4 years after vaccination. These results add to the evidence in support of the use of killed, bivalent, whole-cell oral cholera vaccination as part of comprehensive cholera control plans.FundingUS National Institute of Allergy and Infectious Diseases of the National Institutes of Health and the Bill & Melinda Gates Foundation.

Immune Repertoire after Immunization As Seen by Next-Generation Sequencing and Proteomics.

The immune system produces a diverse repertoire of immunoglobulins in response to foreign antigens. During B-cell development, VDJ recombination and somatic mutations generate diversity, whereas selection processes remove it. Using both proteomic and NGS approaches, we characterized the immune repertoires in groups of rats after immunization with purified antigens. Proteomics and NGS data on the repertoire are in qualitative agreement, but did show quantitative differences that may relate to differences between the biological niches that were sampled for these approaches. Both methods contributed complementary information in the characterization of the immune repertoire. It was found that the immune repertoires resulting from each antigen had many similarities that allowed samples to cluster together, and that mutated immunoglobulin peptides were shared among animals with a response to the same antigen significantly more than for different antigens. However, the number of shared sequences decreased in a log-linear fashion relative to the number of animals that share them, which may affect future applications. A phylogenetic analysis on the NGS reads showed that reads from different individuals immunized with the same antigen populated distinct branches of the phylogram, an indication that the repertoire had converged. Also, similar mutation patterns were found in branches of the phylogenetic tree that were associated with antigen-specific immunoglobulins through proteomics data. Thus, data from different analysis methods and different experimental platforms show that the immunoglobulin repertoires of immunized animals have overlapping and converging features. With additional research, this may enable interesting applications in biotechnology and clinical diagnostics.

Chromosomal transformation inBacillus subtilisis a non-polar recombination reaction

Natural chromosomal transformation is one of the primary driving forces of bacterial evolution. This reaction involves the recombination of the internalized linear single-stranded (ss) DNA with the homologous resident duplex via RecA-mediated integration in concert with SsbA and DprA or RecO. We show that sequence divergence prevents Bacillus subtilis chromosomal transformation in a log-linear fashion, but it exerts a minor effect when the divergence is localized at a discrete end. In the nucleotide bound form, RecA shows no apparent preference to initiate recombination at the 3′- or 5′-complementary end of the linear duplex with circular ssDNA, but nucleotide hydrolysis is required when heterology is present at both ends. RecA·dATP initiates pairing of the linear 5′ and 3′ complementary ends, but only initiation at the 5′-end remains stably paired in the absence of SsbA. Our results suggest that during gene transfer RecA·ATP, in concert with SsbA and DprA or RecO, shows a moderate preference for the 3′-end of the duplex. We show that RecA-mediated recombination initiated at the 3′- or 5′-complementary end might have significant implication on the ecological diversification of bacterial species with natural transformation.

Self-assembly of 12-hydroxystearic acid molecular gels in mixed solvent systems rationalized using Hansen solubility parameters

Recent advances in understanding the underlying mechanisms of self-assembly in molecular gels using Hansen solubility parameters (HSPs) have focused on gelator-single solvent mixtures. Linear correlations between critical gelator concentration (CGC) and polar HSP formed in specific regions where each region has the same proportion of octane with different ratios of either 1-octanol and 1-octylamine. CGC increases with an increasing proportion of 1-octanol and a decreasing proportion of 1-octylamine as the polar HSP increases within each region. Both G′ and breaking points decrease in a log-linear fashion as each individual HSP or total HSP increases, suggesting that 1-octanol-rich gels do not form strong gels because of hydrogen bonding between 1-octanol and 12HSA which is capable of impeding fiber growth. The interaction between 12HSA and 1-octanol is more disruptive to fiber growth than 1-octylamine which arises because of the solvents ability to accept or donate a hydrogen bond.

The Economic Value of Environmental Capital Inputs Used to Produce the Gross Domestic Product in Ghana, 1993 to 2012

Ghana has been one of the fastest growing countries in the world over the last decade driven by exports of oil from newly-discovered offshore oil fields, the export of its traditional commodities of cocoa, gold and other extractive minerals, construction, and the expansion of services related to banking, information and communication technologies, and tourism. Measured by the change in real gross domestic product (GDP), the economy grew at a pace of 7.5% over the period from 2004 to 2013 and 8.6% from 2009 to 2013, and was among the top 15 performers in the world. The Ghanaian economy was formally classified as lower-middle-income in 2010 with a per capita income of over 1,300 United States dollars. Our study focuses on measuring the values of labour and capital inputs used to produce the goods and services incorporated in the GDP. We acknowledge the existence of two types of capital inputs used to produce final goods and services. These are (1) human-made or manufactured capital such as machinery and equipment and (2) environmental capital items such as proven oil and gas reserves, mineral deposits, forest and water resources that are required to produce final goods and services in the economy. We estimated the size of environmental or natural capital stock used to produce the GDP over the twenty-year period, 1993 to 2012 assuming that the economy as a whole exhibited a constant returns to scale feature. The results indicate that over the period, 1993 to 2012, the average share attributed to labour in the production of GDP was about 45%. Human-made capital inputs contributed on average about 19% of GDP. The remaining share of 36% was the estimated value of environmental capital inputs used to produce GDP. We also established that the aggregate environmental depreciation was significantly related to GDP in a positive log-linear fashion while its relationship to real interest rate was negative but not statistically significant.

Liver enzymes and risk of cardiovascular disease in the general population: A meta-analysis of prospective cohort studies

BackgroundGamma glutamyltransferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), commonly used markers of liver dysfunction, have been implicated with risk of cardiovascular disease (CVD). However, the strength and consistency of their associations in the general population have not been reliably quantified. MethodsWe synthesized available prospective epidemiological data on the associations of baseline levels of GGT, ALT, AST, and ALP with CVD [composite CVD, coronary heart disease (CHD), or stroke outcomes]. Relevant studies were identified in a literature search of MEDLINE, EMBASE, and Web of Science up to December 2013. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using random effects models. ResultsTwenty-nine unique cohort studies with aggregate data on over 1.23 million participants and 20,406 cardiovascular outcomes were included. The pooled fully adjusted RRs (95% CIs) for CVD were 1.23 (1.16–1.29) and 1.08 (1.03–1.14) per 1-standard deviation change in log baseline levels of GGT and ALP levels respectively. There was no evidence of an association of ALT or AST with CVD, however, ALT was somewhat inversely associated with CHD 0.95 (0.90–1.00) and positively associated with stroke 1.01 (1.00–1.02) in stratified analysis. Tests for nonlinearity were suggestive of linear relationships of GGT and ALP levels with CVD risk. ConclusionsBaseline levels of GGT and ALP are each positively associated with CVD risk and in a log-linear fashion. There may be variations in the associations of ALT with cause-specific cardiovascular endpoints, findings which require further investigation.

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Cardiovascular diseases have been associated with depression in later life, and a potential mechanism is inhibition of angiogenesis. We designed this study to determine if depression is associated with higher serum concentration of endostatin, an endogenous angiogenesis inhibitor. We performed a cross-sectional examination of a random sample of men aged 69-86 years. Those who scored 7 or higher on the 15-item Geriatric Depression Scale were deemed depressed. We determined the concentration of serum endostatin using a reproducible assay. Other measures included age, education, body mass index, smoking, history of depression, use of antidepressants, hypertension, diabetes, coronary heart disease and stroke, high sensitivity C-reactive protein, plasma homocysteine, triglycerides and cholesterol. We used logistic regression to investigate the association between endostatin and depression, and adjusted the analyses for confounding factors. Our sample included 1109 men. Sixty-three (5.7%) men were depressed. Their serum endostatin was higher than that of nondepressed participants (p = 0.021). Men in the highest decile of endostatin had greater adjusted odds of depression (odds ratio [OR] 1.78, 95% confidence interval [CI] 1.03-3.06). A doubling of endostatin doubled the odds of depression (OR 1.93, 95% CI 1.31-2.84). The probability of depression increased with the concentration of endostatin in a log-linear fashion up to a maximum of about 20%-25%. The cross-sectional design limits the study's ability to ascribe causality to the association between high endostatin and depression. Serum endostatin is associated with depression in older men. It remains to be established whether correction of this imbalance is feasible and could decrease the prevalence of depression in later life.

Hybrid search in the temporal domain: Evidence for rapid, serial logarithmic search through memory

In hybrid search, observers memorize a number of possible targets and then search for any of these in visual arrays of items. Wolfe (2012) has previously shown that the response times in hybrid search increase with the log of the memory set size. What enables this logarithmic search of memory? One possibility is a series of steps in which subsets of the memory set are compared to all items in the visual set simultaneously. In the present experiments, we presented single visual items sequentially in a rapid serial visual presentation (RSVP) display, eliminating the possibility of simultaneous testing of all items. We used a staircasing procedure to estimate the time necessary to effectively detect the target in the RSVP stream. Processing time increased in a log-linear fashion with the number of potential targets. This finding eliminates the class of models that require simultaneous comparison of some memory items to all (or many) items in the visual display. Experiment 3 showed that, similar to visual search, memory search efficiency in this paradigm is influenced by the similarity between the target set and the distractors. These results indicate that observers perform separate memory searches on each eligible item in the visual display. Moreover, it appears that memory search for one item can proceed while other items are being categorized as "eligible" or "not eligible."

Computational model of VEGFR2 pathway to ERK activation and modulation through receptor trafficking

Vascular Endothelial Growth Factor (VEGF) signal transduction is central to angiogenesis in development and in pathological conditions such as cancer, retinopathy and ischemic diseases. We constructed and validated a computational model of VEGFR2 trafficking and signaling, to study the role of receptor trafficking kinetics in modulating ERK phosphorylation in VEGF-stimulated endothelial cells. Trafficking parameters were optimized and validated against four previously published in vitro experiments. Based on these parameters, model simulations demonstrated interesting behaviors that may be highly relevant to understanding VEGF signaling in endothelial cells. First, at moderate VEGF doses, VEGFR2 phosphorylation and ERK phosphorylation are related in a log-linear fashion, with a stable duration of ERK activation; but with higher VEGF stimulation, phosphoERK becomes saturated, and its duration increases. Second, a large endosomal fraction of VEGFR2 makes the ERK activation reaction network less sensitive to perturbations in VEGF dosage. Third, extracellular-matrix-bound VEGF binds and activates VEGFR2, but by internalizing at a slower rate, matrix-bound VEGF-induced intracellular ERK phosphorylation is predicted to be greater in magnitude and more sustained, in agreement with experimental evidence. Fourth, different endothelial cell types appear to have different trafficking rates, which result in different levels of endosomal receptor localization and different ERK response profiles.

Lowered Magnesium in Hypertension

We read with interest the article by Joosten et al1 dealing with urinary magnesium excretion and risk of hypertension—the PREVEND (Prevention of Renal and Vascular End-Stage Disease) study. The authors examined 5511 participants. A total of 1172 developed hypertension. The urinary magnesium excretion was associated with risk of hypertension in an inverse log-linear fashion, and this association remained after adjustment for age, sex, body …

Urinary Magnesium Excretion and Risk of Hypertension

Observational studies on dietary or circulating magnesium and risk of hypertension have reported weak-to-modest inverse associations, but have lacked measures of actual dietary uptake. Urinary magnesium excretion, an indicator of intestinal magnesium absorption, may provide a better insight in this association. We examined 5511 participants aged 28 to 75 years free of hypertension in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study, a prospective population–based cohort study. Circulating magnesium was measured in plasma and urinary magnesium in two 24-hour urine collections, both at baseline. Incident hypertension was defined as blood pressure ≥140 mm Hg systolic or ≥90 mm Hg diastolic, or initiation of antihypertensive medication. During a median follow-up of 7.6 years (interquartile range, 5.0–9.3 years), 1172 participants developed hypertension. The median urinary magnesium excretion was 3.8 mmol/24 hour (interquartile range, 2.9–4.8 mmol/24 hour). Urinary magnesium excretion was associated with risk of hypertension in an inverse log-linear fashion, and this association remained after adjustment for age, sex, body mass index, smoking status, alcohol intake, parental history of hypertension, and urinary excretion of sodium, potassium, and calcium. Each 1-unit increment in ln-transformed urinary magnesium excretion was associated with a 21% lower risk of hypertension after multivariable adjustment (adjusted hazard ratio, 0.79; 95% confidence interval, 0.71–0.88). No associations were observed between circulating magnesium and risk of hypertension. In conclusion, in this cohort of men and women, urinary magnesium excretion was inversely associated with risk of hypertension across the entire range of habitual dietary intake.

Occult breast tumor reservoir: biological properties and clinical significance.

Small, occult, undiagnosed breast cancers are found at autopsy in up to 15.6 % of women dying from unrelated causes with an average of 7 % from eight separate studies. The mammographic detection threshold of breast tumors ranges from 0.88 to 1.66 cm in diameter based on the patient's age. Tumor growth rates, expressed as "effective doubling times," vary from 10 to >700 days. We previously reported two models, based on iterative analysis of these parameters, to describe the biologic behavior of undiagnosed, occult breast tumors. Our models facilitate interpretation of the Women's Health Initiative (WHI) and antiestrogen breast cancer prevention studies. A nude mouse xenograft model was used to validate our assumption that breast tumors grow in a log-linear fashion. We then used our previously reported occult tumor growth (OTG) and computer-simulated tumor growth models to analyze various clinical trial data. Parameters used in the OTG model included a 200-day effective doubling time, 7 % prevalence of occult tumors, and 1.16 cm detection threshold. These models had been validated by comparing predicted with observed incidence of breast cancer in eight different populations of women. Our model suggests that menopausal hormone therapy with estrogens plus a progestogen (E + P) in the WHI trial primarily promoted the growth of pre-existing, occult lesions and minimally initiated de novo tumors. We provide a potential explanation for the lack of an increase in breast cancer incidence in the subgroup of women in the WHI who had not received E + P prior to randomization. This result may have reflected a leftward skew in the distribution of occult tumor doublings and insufficient time for stimulated tumors to reach the detection threshold. Our model predicted that estrogen alone reduced the incidence of breast cancer as a result of apoptosis. Understanding of the biology of occult tumors suggests that breast cancer "prevention" with antiestrogens or aromatase inhibitors represents early treatment rather than a reduction in de novo tumor formation. Our models suggest that occult, undiagnosed tumors are prevalent, grow slowly, and are the biologic targets of a hormone therapy in menopausal women and of antiestrogen therapy for prevention.

Abstract MP23: Urinary Magnesium Excretion and Risk of Incident Hypertension

Background: Observational studies on dietary magnesium and risk of hypertension have reported mixed findings, but have lacked direct measures of magnesium uptake. Urinary excretion of magnesium, an indicator of dietary uptake, may clarify these discrepant findings. Methods: We examined 4,070 participants aged 28-75 years free of hypertension, kidney disease, and cardiovascular disease in the PREVEND Study, a prospective population-based cohort study. Urinary magnesium excretion was measured in two 24-hour urine collections at baseline. Incident hypertension was defined as blood pressure ≥140/90 mm Hg or initiation of antihypertensive medication. Results: During a median follow-up of 7.5 years (interquartile range: 5.5-9.2 years), 1,001 participants developed incident hypertension. Mean 24-hour urinary magnesium excretion was 4.35 ± 1.61 mmol for men and 3.65 ± 1.35 mmol for women. Urinary magnesium excretion was associated with risk of hypertension in a log-linear fashion (Figure) after adjustment for age, body mass index, sex, smoking status, alcohol intake, family history of hypertension, and urinary excretion of sodium, potassium, and calcium. Each 1-unit increment in ln-transformed urinary magnesium excretion was associated with a 26% lower risk of incident hypertension after multivariable adjustment (adjusted hazard ratio, 0.74; 95% confidence interval, 0.65-0.84). Conclusion: Urinary magnesium excretion is inversely and independently associated with risk of incident hypertension. Increasing dietary intake of magnesium could reduce the risk of hypertension. Figure legend: Natural log-transformed urinary magnesium concentrations and adjusted risk of hypertension. Magnesium levels were back-transformed to original values for ease of interpretation. Association estimated by Cox regression based on restricted splines with three knots. Dashed lines represent the 95% confidence interval. The spline curve is truncated at the 0.5 percentile and 99.5 percentile of the distribution curve.