To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
To investigate the association between folate levels and the risk of gestational diabetes mellitus (GDM) risk during the whole pregnancy.
In this retrospective cohort study of pregnant women, serum folate levels were measured before 24 gestational weeks (GW). GDM was diagnosed between 24th and 28th GW based on the criteria of the International Association of Diabetes and Pregnancy Study Groups. General linear models were performed to examine the association of serum folate with plasma glucose (i.e. linear regressions) and risk of GDM (i.e. log-binomial regressions) after controlling for confounders. Restricted cubic spline regression was conducted to test the dosage–response relationship between serum folate and the risk of GDM.
A sigle, urban hospital in Shanghai, China.
A total of 42 478 women who received antenatal care from April 2013 to March 2017 were included.
Consistent positive associations were observed between serum folate and plasma glucose levels (fasting, 1-h, 2-h). The adjusted relative risks (RR) and 95 % CI of GDM across serum folate quartiles were 1·00 (reference), 1·15 (95 % CI (1·04, 1·26)), 1·40 (95 % CI (1·27, 1·54)) and 1·54 (95 % CI (1·40, 1·69)), respectively (P-for-trend < 0·001). The positive association between serum folate and GDM remained when stratified by vitamin B12 (adequate v. deficient groups) and the GW of serum folate measurement (≤13 GW v. >13 GWs)
The findings of this study may provide important evidence for the public health and clinical guidelines of pregnancy folate supplementation in terms of GDM prevention.
Healthcare-associated infection (HAI) is a major cause of morbidity, mortality and cost, which vary widely by region and hospital. In this case-control study, we calculated losses attributable to HAI in central China. A total of 2976 patients in 10 hospitals were enrolled, and the incidence rate of HAI (range, 0.88–4.15%) was significantly, but negatively associated with the cost per 1000 beds of its prevention (range, $24 929.76–$53 146.41; r = −0.76). The per capita economic loss attributable to HAIs was $2047.07 (interquartile range, $327.63–$6429.17), mainly from the pharmaceutical cost (median, $1044.39). The HAIs, which occurred in patients with commercial medical insurance, affected the haematologic system and caused by Acinetobacter baumannii, contributed most to the losses (median, $3881.55, $4734.20 and $9882.75, respectively). Furthermore, the economic losses attributable to device-associated infections and hospital-acquired multi-drug resistant bacteria were two to four times those of the controls. The burden attributable to HAI is heavy, and opportunities for easing this burden exist in several areas, including that strengthening antibiotic stewardship and practicing effective bundle of HAI prevention for patients carrying high-risk factors, for example, elders or those with catheterisations in healthcare institutions, and accelerating the medical insurance payment system reform based on diagnosis-related groups by policy-making departments.
We aimed to examine the association between the quantity and quality of dietary fat in early pregnancy and gestational diabetes mellitus (GDM) risk. In total, 1477 singleton pregnant women were included from Sichuan Provincial Hospital for Women and Children, Southwest China. Dietary information was collected by a 3-d 24-h dietary recall. GDM was diagnosed based on the results of a 75-g, 2-h oral glucose tolerance test at 24–28 gestational weeks. Log-binomial models were used to estimate relative risks (RR) and 95% CI. The results showed that total fat intake was positively associated with GDM risk (Q4 v. Q1: RR = 1·40; 95 % CI 1·11, 1·76; Ptrend = 0·001). This association was also observed for the intakes of animal fat and vegetable fat. After stratified by total fat intake (< 30 %E v. ≥ 30 %E), the higher animal fat intake was associated with higher GDM risk in the high-fat group, but the moderate animal fat intake was associated with reduced risk of GDM (T2 v. T1: RR = 0·65; 95 % CI 0·45, 0·96) in the normal-fat group. Vegetable fat intake was positively associated with GDM risk in the high-fat group but not in the normal-fat group. No association between fatty acids intakes and GDM risk was found. In conclusion, total fat, animal and vegetable fat intakes were positively associated with GDM risk, respectively. Whereas when total fat intake was not excessive, higher intakes of animal and vegetable fat were likely irrelevant with increased GDM risk, even the moderate animal fat intake could be linked to lower GDM risk.
The three-parameter generalized gamma (TPGG) distribution is a generalization of the two-parameter gamma distribution and includes as special cases the exponential distribution, the two-parameter gamma distribution, the Weibull distribution, and the lognormal distribution that are employed for frequency analysis in water engineering. In this chapter, the TPGG distribution is derived using the entropy theory and then its parameters are estimated with the principle of maximum entropy and the methods of maximum likelihood estimation and moments.
A multitude of processes in hydrology and environmental engineering are either random or entail random components which are characterized by random variables. These variables are described by frequency distributions. This book provides an overview of different systems of frequency distributions, their properties, and applications to the fields of water resources and environmental engineering. A variety of systems are covered, including the Pearson system, Burr system, and systems commonly applied in economics, such as the D'Addario, Dagum, Stoppa, and Esteban systems. The latter chapters focus on the Singh system and the frequency distributions deduced from Bessel functions, maximum entropy theory, and the transformations of random variables. The final chapter introduces the genetic theory of frequency distributions. Using real-world data, this book provides a valuable reference for researchers, graduate students, and professionals interested in frequency analysis.
The four-parameter exponential gamma (FPEG) distribution can be applied to frequency analysis of a range of random variables, such as floods, drought, wind velocity, and rainfall. The FPEG distribution is versatile and gives rise to a number of distributions that are popularly used for frequency analyses in environmental and water engineering. This chapter discusses the characteristics of this distribution and the estimation of its parameters using different methods.
The Halphen type B (Hal-B) frequency distribution has been employed for frequency analyses of hydrometeorological and hydrological extremes. This chapter derives this distribution using entropy theory and discusses the estimation of its parameters with the use of the constraints used for their derivation. The distribution i+L13s tested using entropy and the methods of moments and maximum likelihood estimation.
The kappa distribution has been applied to study the frequency of hydrological events. This chapter discusses the kappa distribution and its parameter estimation using the methods of entropy, maximum likelihood, and moments.
The Halphen type inverse B (Hal-IB) distribution is obtained from the Halphen type B distribution. This chapter discusses the derivation of the Hal-IB distribution and its characteristics and the estimation of its parameters using the methods of maximum entropy, moments, and maximum likelihood.
The five-parameter Feller–Pareto distribution may be considered as a generalization of the two-parameter beta distribution through transformation. In this chapter, the five-parameter Feller–Pareto distribution is derived using entropy theory and then its parameters are estimated with the principle of maximum entropy and the methods of maximum likelihood estimation and moments. Synthetic data from true population and real-world data including peak flow, maximum daily precipitation, and total flow deficit are applied to evaluate the performance of different estimation methods.
The Burr–Singh–Maddala (BSM) probability distribution is a generalization of the Pareto distribution and the Weibull distribution that are used for frequency analyses of a variety of hydrologic and hydrometeorologic data. This distribution possesses a number of interesting characteristics that are discussed in this chapter. The BSM distribution is derived using the entropy theory, which then is applied to derive the BSM distribution parameters. Real-world data are used to illustrate the application of the distribution.
The Halphen type A (Hal-A) frequency distribution has been employed for frequency analyses of hydrometeorological and hydrological extremes. This chapter derives this distribution using entropy theory and discusses the estimation of its parameters using the methods of entropy, moments, probability moments, L-moments, cumulative moments, and maximum likelihood estimation.
The four-parameter beta Lomax (FPBL) distribution is a generalization of the beta distribution through random variable transformation. The FPBL distribution may be reduced to three-parameter distribution and may also be extended to five-parameter beta Lomax distribution by adding the location parameter. In this chapter, the FPBL distribution is derived using the entropy theory and then its parameters are estimated with the principle of maximum entropy and the method of maximum likelihood estimation.