Application of machine learning algorithms to predict osteoporosis in postmenopausal women with type 2 diabetes mellitus

PURPOSE

The screening and diagnosis of osteoporosis in patients with type 2 diabetes mellitus (T2DM) based on bone mineral density remains challenging because of the limited availability and accessibility of dual-energy X-ray absorptiometry. We aimed to develop and validate models to predict the risk of osteoporosis in postmenopausal women with T2DM based on machine learning (ML) algorithms.

METHODS

This retrospective study included 303 postmenopausal women with T2DM. To develop prediction models for osteoporosis, we applied nine ML algorithms combined with demographic, clinical, and laboratory data. The least absolute shrinkage and selection operator were used to perform feature selection. We used the bootstrap resampling technique for model training and validation. To test the performance of the models, we calculated indices including the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, F1 score, calibration curve, and decision curve analysis. Furthermore, we conducted fivefold cross-validation for parameter optimization and model validation. Feature importance was assessed using the SHapley additive explanation (SHAP).

RESULTS

We identified 10 independent predictors as the most valuable features. An AUROC of 0.616-1.000 was observed for nine ML algorithms. The extreme gradient boosting (XGBoost) model exhibited the best performance, outperforming conventional risk assessment tools and registering 0.993 in the training set, 0.798 in the validation set, and 0.786 in the test set for fivefold cross-validation. Using SHAP, we found that the explanatory variables contributed to the model and their relationship with osteoporosis occurrence. Furthermore, we developed a user-friendly tool for calculating the risk of osteoporosis.

CONCLUSIONS

With the integration of demographic and clinical risk factors, ML algorithms can accurately predict osteoporosis. The XGBoost model showed ideal performance. With the incorporation of these models in the clinic, patients may benefit from early osteoporosis diagnosis and treatment.

Primary specification of blastocyst trophectoderm by scRNA-seq: New insights into embryo implantation

Mechanisms of implantation such as determination of the attachment pole, fetal-maternal communication, and underlying causes of implantation failure are largely unexplored. Here, we performed single-cell RNA sequencing on peri-implantation embryos from both humans and mice to explore trophectoderm (TE) development and embryo-endometrium cross-talk. We found that the transcriptomes of polar and mural TE diverged after embryos hatched from the zona pellucida in both species, with polar TE being more mature than mural TE. The implantation poles show similarities in cell cycle activities, as well as in expression of genes critical for implantation and placentation. Embryos that either fail to attach in vitro or fail to implant in vivo show abnormalities in pathways related to energy production, protein metabolism, and 18S ribosomal RNA m⁶A methylation. These findings uncover the gene expression characteristics of humans and mice TE differentiation during the peri-implantation period and provide new insights into embryo implantation.

Regional and developmental characteristics of human embryo mosaicism revealed by single cell sequencing

Chromosomal mosaicism is common throughout human pre- and post-implantation development. However, the incidence and characteristics of mosaicism in human blastocyst remain unclear. Concerns and confusions still exist regarding the interpretation of chromosomal mosaicism on preimplantation genetic testing for aneuploidy (PGT-A) results and embryo development. Here, we aimed to estimate the genetic concordance between trophectoderm (TE), inner cell mass (ICM) and the corresponding human embryonic stem cells (hESCs), and to explore the characteristics of mosaicism in human blastocyst and hESCs on a single cell level. The single cell sequencing results of TE cells indicated that 65.71% of the blastocysts were mosaic (23 in 35 embryos), while the ICM sequencing results suggested that 60.00% of the blastocysts were mosaic (9 in 15 embryos). The incidence of mosaicism for the corresponding hESCs was 33.33% (2 in 6 embryos). No significant difference was observed between the mosaic rate of TE and that of ICM. However, the mosaic rate of the corresponding hESCs was significantly lower than that of TE and ICM cells, suggesting that the incidence of mosaicism may decline during embryonic development. Upon single cell sequencing, we found several “complementary” copy number variations (CNVs) that were usually not revealed in clinical PGT-A which used multi-cell DNA sequencing (or array analysis). This indicates the potential diagnostic risk of PGT-A based multi-cell analysis routinely in clinical practice. This study provided new insights into the characteristics, and considerable influences, of mosaicism on human embryo development, as well as the clinical risks of PGT-A based on multi-cell biopsies and bulk DNA assays.

Chromosomal mosaicism is a common biological phenomenon during human embryo development, which may have interferences with clinical PGT-A decision-making. In this study, single cell DNA sequencing and copy number variation (CNV) analysis were performed to estimate the genetic concordance of TE, ICM, and hESCs. The single cell sequencing results of TE cells indicated that 65.71% of the blastocysts were mosaic, while the ICM sequencing result suggested that 60.00% of the blastocysts were mosaic in the 39 embryos we analyzed. The mosaicism may be caused by both whole and segmental abnormalities of the chromosome. Our study described the characteristics of chromosome mosaicism on single cell level in human embryo and brought evidence that mosaicism could raise challenges in the clinical management of PGT-A.

Dissecting Human Gonadal Cell Lineage Specification and Sex Determination Using A Single-cell RNA-seq Approach

Gonadal somatic cells are the main players in gonad development and are important for sex determination and germ cell development. Here, using a time-series single-cell RNA sequencing (scRNA-seq) strategy, we analyzed fetal germ cells (FGCs) and gonadal somatic cells in human embryos and fetuses. Clustering analysis of testes and ovaries revealed several novel cell subsets, including POU5F1⁺SPARC⁺ FGCs and KRT19⁺ somatic cells. Furthermore, our data indicated that the bone morphogenetic protein (BMP) signaling pathway plays cell type-specific and developmental stage-specific roles in testis development and promotes the gonocyte-to-spermatogonium transition (GST) in late-stage testicular mitotic arrest FGCs. Intriguingly, testosterone synthesis function transitioned from fetal Sertoli cells to adult Leydig cells in a stepwise manner. In our study, potential interactions between gonadal somatic cells were systematically explored and we identified cell type-specific developmental defects in both FGCs and gonadal somatic cells in a Turner syndrome embryo (45, XO). Our work provides a blueprint of the complex yet highly ordered development of and the interactions among human FGCs and gonadal somatic cells.

[Clinical characteristics, surgical treatment and prognosis of rolandic and perirolandic drug-resistant epilepsies]

Objective: To explore the clinical characteristics, treatment strategies and prognosis of rolandic and perirolandic drug-resistant epilepsies (DREs). Methods: The clinical data of 53 patients diagnosed with rolandic or perirolandic DRE who were admitted to Epilepsy Center, Sanbo Brain Hospital of Capital Medical University from January 2008 to January 2019 were retrospectively analyzed. The patients were divided into resective therapy group and non-resective therapy group [bipolar electrocoagulation on cortex, stereotactic electroencephalography (SEEG)-guided radiofrequency thermocoagulation, and vagus nerve stimulation]. The outcomes of epilepsy and post-surgical limb function were compared and analyzed. Results: A total of 53 patients were included, aged from 3 to 45 years old [(19±11) years], with 33 males and 20 females. Thirty patients received resective therapy and 23 patients received non-resective therapy. The curative effect of the resective therapy group was significantly better than that of the non-resective therapy group. The rate of Engel Ⅰ in resective therapy group was higher than that of non-resective group [83.3% (25/30) vs 39.1% (9/23), P=0.011). Compared with the non-resective group, the incidence of muscle strength decline in the resective group was higher both at 1 week [73.3% (22/30) vs 21.7% (5/23), P=0.006] and 3 months [30% (9/30) vs 0, P=0.016] after surgery. Conclusions: During the diagnosis and treatment, the multimodal method is conducive to the qualitative and localized diagnosis of the rolandic or perirolandic epilepsy, while SEEG has important value in the diagnosis, functional localization and treatment of the disease. Resective therapy is still the most effective method to terminate epilepsy, but it has a higher risk of post-surgical dysfunction.

Clinical application of an NGS-based method in the preimplantation genetic testing for Duchenne muscular dystrophy

PURPOSE

To determine whether next-generation sequencing (NGS) could be used to directly detect different mutations of Duchenne muscular dystrophy (DMD) during preimplantation genetic testing (PGT).

METHODS

From Sep. 2016 to Aug. 2018, a total of six couples participated in this study. Four cases carried DMD exon deletions and two carried exon duplications. Trophectoderm cells were biopsied at day 5 or 6 and NGS was used in the genetic testing of the biopsied cells after whole-genome amplification. We developed a new method-DIRected Embryonic Cell Testing of Exon Deletion/Duplication (DIRECTED) to directly detect the single-gene mutation by NGS. Linage analysis based on single-nucleotide polymorphism (SNP) was used to validate the results from DIRECTED.

RESULTS

In the four deletion cases, DIRECTED was used to detect DMD exon deletion in 16 biopsied embryos. All DIRECTED results were consistent with linkage analysis, indicating this method was reliable in detecting deletions around 1 Mb. In the two cases carrying exon duplications, no blastocyst was obtained for biopsy. Nonetheless, preliminary experiment results suggested that DIRECTED could also be used for direct detection of exon duplications in embryos.

CONCLUSIONS

Exon deletions or duplications in DMD of preimplantation embryos could be detected directly by NGS-based methods during PGT.

The methylome of a human polar body reflects that of its sibling oocyte and its aberrance may indicate poor embryo development

STUDY QUESTION

Is it possible to evaluate the methylome of individual oocytes to investigate the DNA methylome alterations in metaphase II (MII) oocytes with reduced embryo developmental potential?

SUMMARY ANSWER

The DNA methylome of each human first polar body (PB1) closely mirrored that of its sibling MII oocyte; hypermethylated long interspersed nuclear element (LINE) and long terminal repeats (LTRs) and methylation aberrations in PB1 promoter regions may indicate poor embryo development.

WHAT IS KNOWN ALREADY

The developmental potential of an embryo is determined by the oocyte's developmental competence, and the PB1 is a good substitute to examine the chromosomal status of the corresponding oocyte. However, DNA methylation, a key epigenetic modification, also regulates gene expression and embryo development.

STUDY DESIGN, SIZE, DURATION

Twelve pairs of PB1s and sibling MII oocytes were biopsied and sequenced to compare their methylomes. To further investigate the methylome of PB1s and the potential epigenetic factors that may affect oocyte quality, MII oocytes (n = 74) were fertilized through ICSI, while PB1s were biopsied and profiled to measure DNA methylation. The corresponding embryos were further cultured to track their development potential. The oocytes and sperm samples used in this study were donated by healthy volunteers with signed informed consent.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Single-cell methylome sequencing was applied to obtain the DNA methylation profiles of PB1s and oocytes. The DNA methylome of PB1s was compared between the respective group of oocytes that progressed to blastocysts and the group of oocytes that failed to develop. DNA methylation levels of corresponding regions and differentially methylated regions were calculated using customized Perl and R scripts. RNA-seq data were downloaded from a previously published paper and reanalysed.

MAIN RESULTS AND THE ROLE OF CHANCE

The results from PB1-MII oocyte pair validated that PB1 contains nearly the same methylome (average Pearson correlation is 0.92) with sibling MII oocyte. LINE and LTR expression increased markedly after fertilization. Moreover, the DNA methylation levels in LINE (including LINE1 and LINE2) and LTR were significantly higher in the PB1s of embryos that could not reach the blastocyst stage (Wilcoxon-Matt-Whitney test, P < 0.05). DNA methylation in PB1 promoters correlated negatively with gene expression of MII oocyte. Regarding the methylation status of the promoter regions, 66 genes were hypermethylated in the developmental arrested group, with their related functions (significantly enriched in several Gene Ontology terms) including transcription, positive regulation of adenylate cyclase activity, mitogen-activated protein kinase (MAPK) cascade and intracellular oestrogen receptor signalling pathway.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Data analysis performed in this study focused on the competence of human oocytes and compared them with maternal genetic and epigenetic profiles. Therefore, data regarding the potential regulatory roles of paternal genomes in embryo development are lacking.

WIDER IMPLICATIONS OF THE FINDINGS

The results from PB1-oocyte pairs demonstrated that PB1s shared similar methylomes with their sibling oocytes. The selection of the good embryos for transfer should not only rely on morphology but also consider the DNA methylation of the corresponding PB1 and therefore MII oocyte. The application of early-stage analysis of PB1 offers an option for high-quality oocyte and embryo selection, which provides an additional tool for elective single embryo transfer in assisted reproduction.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Key Research and Development Program of China (2018YFC1004003, 2017YFA0103801), the National Natural Science Foundation of China (81730038, 3187144, 81521002) and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16020703). The authors have no conflicts of interest to declare.

A comprehensive PGT-M strategy for ADPKD patients with de novo PKD1 mutations using affected embryo or gametes as proband

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease characterized by the development of renal cysts and progression to renal failure. Preimplantation genetic testing-monogenic disease (PGT-M) is an alternative option to obtain healthy babies. However, de novo PKD1 mutation of one of the spouses or the absence of a positive family history poses a serious challenge to PGT-M. Here, we described a comprehensive strategy which includes preimplantation genetic testing for aneuploidies (PGT-A) study and monogenic diagnosis study for ADPKD patients bearing de novo mutations. The innovation of our strategy is to use the gamete (polar body or single sperm) as proband for single-nucleotide polymorphism (SNP) linkage analysis to detect an embryo's carrier status. Nine ADPKD couples with either de novo mutation or without a positive family history were recruited and a total of 34 embryos from 13 PGT-M cycles were examined. Within these nine couples, two successfully delivered healthy babies had their genetic status confirmed by amniocentesis. This study provides a creative approach for embryo diagnosis of patients with de novo mutations or patients who lack essential family members for linkage analysis.

5-Formylcytosine landscapes of human preimplantation embryos at single-cell resolution

Epigenetic dynamics, such as DNA methylation and chromatin accessibility, have been extensively explored in human preimplantation embryos. However, the active demethylation process during this crucial period remains largely unexplored. In this study, we use single-cell chemical-labeling-enabled C-to-T conversion sequencing (CLEVER-seq) to quantify the DNA 5-formylcytosine (5fC) levels of human preimplantation embryos. We find that 5-formylcytosine phosphate guanine (5fCpG) exhibits genomic element-specific distribution features and is enriched in L1 and endogenous retrovirus-K (ERVK), the subfamilies of repeat elements long interspersed nuclear elements (LINEs) and long terminal repeats (LTRs), respectively. Unlike in mice, paired pronuclei in the same zygote present variable difference of 5fCpG levels, although the male pronuclei experience stronger global demethylation. The nucleosome-occupied regions show a higher 5fCpG level compared with nucleosome-depleted ones, suggesting the role of 5fC in organizing nucleosome position. Collectively, our work offers a valuable resource for ten-eleven translocation protein family (TET)-dependent active demethylation-related study during human early embryonic development.

Utility of arterial spin labelling MRI for discriminating atypical high-grade glioma from primary central nervous system lymphoma

AIM

To evaluate the ability of arterial spin labelling (ASL) magnetic resonance imaging (MRI) in differentiating primary central nervous system lymphoma (PCNSL) from atypical high-grade glioma (HGG), as well as exploring the underlying pathological mechanisms.

METHODS AND MATERIALS

Twenty-three patients with PCNSL and 17 patients with atypical HGG who underwent ASL-MRI were identified retrospectively. Absolute cerebral blood flow (aCBF) and normalised cerebral blood flow (nCBF) values were obtained, and were compared between PCNSL and atypical HGG using the Mann-Whitney U-test. The performance in discriminating between PCNSL and atypical HGG was evaluated using receiver-operating characteristics analysis and area-under-the-curve (AUC) values for aCBF and nCBF. The correlation between microvessel density (MVD) and aCBF was determined by Spearman's correlation analysis.

RESULTS

Atypical HGG demonstrated significantly higher aCBF, nCBF, and MVD values than PCNSL (p<0.05). The diagnostic accuracy of discriminating PCNSL from atypical HGG showed AUC=0.877 (95% confidence interval [CI] 0.735-0.959) for aCBF, and AUC=0.836 (95% confidence interval [CI] 0.685-0.934) for nCBF. There was a moderate positive correlation between aCBF values of region of interest (ROI >30 mm²) in the enhanced area and MVD values (rho=0.579, p=0.0001), and a strong positive correlation between aCBF values MVD based on "point-to-point biopsy" (rho=0.83, p=0.0029). Interobserver agreements for aCBF and nCBF were excellent (ICC >0.75).

CONCLUSIONS

ASL perfusion MRI is a useful imaging technique for the discrimination between atypical HGG and PCNSL, which may be determined by the difference of MVD between them.

[Neuropathologic findings in intractable epilepsy: a clinicopathologic analysis of 822 cases]

Objective: To investigate the clinicopathologic characteristics of intractable epilepsy. Methods: Based on the classification criteria proposed by the International League Against Epilepsy (ILAE), a retrospective analysis of the pathological characteristics was done in 822 patients who underwent epilepsy surgery in Sanbo Brain Hospital, Capital Medical University, from June 2008 to December 2012. Results: The mean age of epilepsy onset was 9.9 years, mean duration of epilepsy was 11.9 years. Complex partial seizures were the main presenting features. Histopathological study showed 33 cases (4.01%) with mild forms of cortical malformations, 690 cases (83.94%) with focal cortical dysplasia (FCD) and 99 cases with others (including 39 pure hippocampal sclerosis, 20 cystosclerosis, 19 Sturge-Weber syndrome, 8 tuberous sclerosis complex, 6 without significant pathological changes, 5 gyral malformations and 2 hamartoma). Among the 690 FCD cases, 106 were FCD typeⅠ, 91 were FCD typeⅡ and 493 were FCDⅢ(Ⅲa: 160, Ⅲb: 106, Ⅲc: 26 and Ⅲd: 201). Conclusions: FCDⅢd is the most common histopathological subtype causing intractable epilepsy, mainly due to focal hypoxia/ischemia in the perinatal period, which results in scarring of local brain tissue; this is followed by other isolated forms of FCD (FCDⅠand FCDⅡ), and then FCD Ⅲa and FCD Ⅲb. The reason to distinguish isolated forms of FCD (types Ⅰ and Ⅱ) from FCD Ⅲ and to subclassify FCD Ⅲ is to allow better definition of cortical dyslamination. Therefore, the pathogenic factors of intractable epilepsy can be grouped in greater details, and facilitate the diagnosis and potential curative treatment of intractable epilepsy.

Fatty and lean red meat consumption in China: differential association with Chinese abdominal obesity

AIM

We examined the longitudinal association between red meat (RM) consumption and the risk of abdominal obesity in Chinese adults.

METHODS AND RESULTS

Our data are from 16,822 adults aged 18-75 in the China Health and Nutrition Survey from 1993 to 2011. We assessed RM intake with three 24-h dietary recalls. We defined abdominal obesity as a waist circumference (WC) ≥85 centimeters (cm) for men and ≥80 cm for women. Multilevel mixed-effect regression models showed that men experienced WC increases of 0.74 cm (95% confidence interval [CI]: 0.39-1.09) from a higher total intake of fresh RM and 0.59 cm (95% CI: 0.24-0. 95) from a higher intake of fatty fresh RM but 0.14 cm (95% CI: -0.39 to 0.66) from a higher intake of lean fresh RM in the top quartile versus non-consumers when adjusted for potential confounders. In contrast, after additional adjustment for baseline WC, the odds ratios of abdominal obesity in men were attenuated for total fresh RM (1.25 [95% CI: 1.06-1.47]) and fatty fresh RM (1.22 [95% CI: 1.03-1.44]) but were still not affected by lean fresh RM (0.95 [95% CI: 0.75-1.22]). Women also showed a positive association of fatty fresh RM intake with abdominal obesity.

CONCLUSION

Greater intake of fatty fresh RM was significantly associated with higher WC (men only) and abdominal obesity risk in Chinese adults. The gender-specific differential association of fatty versus lean fresh RM warrants further study.

Nutrition of elderly people in China

Cross-sectional data from the 1991 (n = 1657) and 1993 (n = 1773) China Health and Nutrition Surveys were used to describe patterns in the diets, activity levels and body mass index (BMI) of elderly Chinese (aged 60 or older). In 1991 and 1993, the prevalence of low BMI (BMI < 18.5 or BMI < 22.0) exceeded 15%, while the prevalence of high BMI (BMI > 25.0 or BMI > 27.0) ranged between 4% and 24%. The BMI was consistently, positively and significantly associated with urban residence. Urban residence and income were consistently and positively associated with energy from fat and protein intakes, and decreasing physical activity levels. The results suggest that under- and overnutrition coexist among Chinese elders and are differentially distributed across income and urban/rural strata.

Programme and policy options for preventing obesity in China

By 2002, China's prevalence of overweight and obesity among adults was 18.9 and 2.9%, respectively. The replacement of traditional Chinese diet with 'Western diet', major declines in all phases of activity and increased sedentary activity are cited as the main reasons explaining the rapid increase in overweight and obesity, which bring major economic and health costs. The Nutrition Improvement Work Management Approach was released in 2010. Overweight and obesity prevention-related policies were added to national planning for disease prevention and control. The Guidelines for Prevention and Control of Overweight and Obesity of Chinese Adults and the School-age Children and Teenagers Overweight and Obesity Prevention and Control Guidelines in China were promulgated in 2003 and 2007, respectively. Few education programmes have been implemented. Selected academic intervention research projects dominate with a focus on reducing child obesity and promoting healthier diets; increasing physical activity and reducing sedentary time; and facilitating changes in family, school, social and cultural environments. Intervention samples are small and have not addressed the increasing rates of obesity throughout the entire population. Government provision of effective policy measures, multisectoral cooperation and increasing corporate social responsibility are keys to curbing the trend towards overweight and obesity in China.

Valley-dependent Brewster angles and Goos-Hänchen effect in strained graphene

We demonstrate theoretically how local strains in graphene can be tailored to generate a valley-polarized current. By suitable engineering of local strain profiles, we find that electrons in opposite valleys (K or K') show different Brewster-like angles and Goos-Hänchen shifts, exhibiting a close analogy with light propagating behavior. In a strain-induced waveguide, electrons in K and K' valleys have different group velocities, which can be used to construct a valley filter in graphene without the need for any external fields.

Physical activity level and its association with metabolic syndrome among an employed population in China

The purpose of the present study was to estimate the association of physical activity level (PAL) with metabolic syndromes among the employed population in China. Using data from the 2002 China National Nutrition and Health Survey, the PAL of 21 834 subjects aged 18-59 years was described, and its relationship with the risk of metabolic syndrome was studied after adjusting for the relative effects of smoking, drinking, diet and socioeconomic status. Information on physical activity was collected by trained investigators using a 1-year physical activity questionnaire. PAL was classified into four categories: sedentary (PAL 1.00-1.39), low active (PAL 1.40-1.59), active (PAL 1.60-1.89) and very active (PAL 1.90-2.50). The definition of metabolic syndrome by the International Diabetes Federation 2005 was applied. The percentage of people being sedentary, low active, active and very active was 12.3%, 13.7%, 20.1% and 53.9% respectively. The crude prevalence of metabolic syndrome in the sedentary, low active, active and very active groups was 9.7%, 6.9%, 5.6% and 4.9% respectively. After adjusting for the effect of other risk factors, the higher the PAL, the lower the relative risk of metabolic syndrome as well as the individual metabolic abnormalities. The risk of overweight/obesity and metabolic syndrome was 50% and 59% less, respectively, in the adults who were very active and whose dietary fat contributed less than 20% to energy intakes when compared with their counterparts who were sedentary and consumed more fat (> or = 30% energy). PAL was an independent risk factor for obesity and multiple metabolic syndrome abnormalities among the employed population in China. The high-risk population were middle-age males living in large cities with high incomes who drink alcohol.

Closing the energy gap to prevent weight gain in China

To estimate the energy gap (i.e. degree of positive energy balance) that is causing weight gain in the population of China in order to provide a quantitative goal for how much behaviour change is required to prevent excess weight gain in the population. This is based on data collected in the China Health and Nutrition Survey. 2288 adults (20-45 years) who took part in both the 1989 and 2000 surveys were selected.

RESULTS

from 1989 to 2000, the average weight of this population increased from 55.4 kg to 59.1 kg. The medium increasing rate was 0.33 kg year(-1). During this time, the prevalence of overweight in the population increased dramatically from 9.0% to 23.2%. By assuming that each kilogram of body weight gained represents 7700 kcal, the estimated medium energy accumulation in the sample was 7.0 kcal day(-1) and the 90th percentile was 22.5 kcal d(-1). Further, assuming that the energy derived from mixed composition diets is stored with an average efficiency of 50%, the estimated energy gap for the population was 45 kcal day(-1). This is the degree of positive energy balance that is causing weight gain in 90% of the population. The estimate suggests that the behaviour change needed to close the energy gap is small and achievable without dramatically altering current lifestyle in China. For example, reducing energy intake by just 2-3% less each day or walking an extra 10-15 minutes each day could offset weight gain in roughly 90% of the population in China. By providing an estimate of the energy gap it can be predicted that weight gain in most of the population of China could be prevented with small lifestyle changes. It is critical that these lifestyle changes be implemented in order to prevent acceleration of the obesity epidemic in China.

Childhood obesity and its health consequence in China

Analyses of data from the representative 2002 National Nutrition and Health Survey were used to assess the likelihood of metabolic complications of overweight and obesity in Chinese children aged 7-17 years. Chinese criteria for body mass index classification were used for overweight and obesity with the 75th percentile US adolescent values for waist circumferences and all the metabolic criteria for blood pressure, lipids, fasting glucose established for US adolescents. Diabetes in 7-12-year-olds was 0.2% and 0.4% in children aged 12-18 years. Prevalences of dyslipidaemia (61.9%), hypertriglyceridaemia (18.2%) and low high-density lipoprotein cholesterol (56.1%) were high and 16.0% of 15-18 years had hypertension. The overall prevalence of the metabolic syndrome was 3.3% with more than half the children having at least one metabolic abnormality and 19.8% having at least two. All the metabolic parameters were significantly elevated in the overweight and obese children except high-density lipoprotein cholesterol. These data emphasize the marked sensitivity of Chinese children to the metabolic complications of overweight and obesity and amplify the need for early preventive measures.

Prevalence of the metabolic syndrome in Chinese adolescents

Since national figures on the occurrence of metabolic syndrome among Chinese adolescents are lacking, this study aims to estimate its prevalence and distribution among Chinese youngsters. The 2002 China National Nutrition and Health Survey is a nationally representative cross-sectional study. Applying the criteria for US adolescents, we estimated the prevalence of metabolic syndrome among 2761 adolescents aged 15 to 19 years. The prevalence of metabolic syndrome among Chinese adolescents overall was 3.7 % (10 % in US adolescents). It was 35.2 %, 23.4 % and 2.3 % among adolescents who were overweight (BMI > or = 95th percentile), at risk of overweight (BMI between 85th and 95th percentile) and normal weight (BMI below the 85th percentile), respectively. Urban boys had the highest rate (5.8 %) compared with girls and rural youngsters. Among adolescents who had a BMI > or = 85th percentile and one or two parent(s) with metabolic syndrome, the prevalence was 46.4 %. A total of 96 % of overweight adolescents had at least one and 74.1 % overweight adolescents had at least two abnormalities of metabolic syndrome. Based on these figures, it is estimated that more than three million Chinese adolescents have metabolic syndrome. Both overweight and metabolic syndrome prevalence among adolescents are still relatively low in China, but the prevalence of metabolic syndrome among Chinese overweight adolescents is similar to those living in the USA.

Longitudinal relationships between occupational and domestic physical activity patterns and body weight in China

OBJECTIVES

To examine the longitudinal relationship between occupational and domestic sources of physical activity and body weight in a sample of Chinese adults.

METHODS

Population-based longitudinal observational study of Chinese adults (4697 women and 4708 men) aged 18-55 from the 1991, 1993, 1997, and 2000 waves of the China Health and Nutrition Survey. Measured height and weight and detailed self-reported energy expenditure from multiple occupational and domestic sources were assessed over a 9-year period. Longitudinal relationships were modeled using linear random effects models.

RESULTS

Increased occupational physical activity resulted in overall lower body weight for both men and women (beta-coefficients (95% confidence interval (CI)) for high levels: -0.46 (-0.76, -0.15) for men, -0.36 (-0.62, -0.10) for women, and increased domestic physical activity resulted in overall lower body weight in men (beta-coefficient (95% CI): -0.40 (-0.62, -0.18)).

CONCLUSIONS

Physical activity that occurs in the occupational and domestic sectors is often overlooked; yet our research suggests they have important effects on body weight in Chinese adults. As China continues to urbanize, energy expenditure from these sources is decreasing, and our results point out the need to explore these types of physical activity more broadly across the world as potential sources of weight gain.

Determinants of childhood overweight and obesity in China

In order to investigate the determinants of childhood overweight and obesity in China, the prevalence of overweight (including obesity) was compared according to different dietary and physical activity patterns and parental body weight status. A total of 6826 children aged 7-17 years from the 2002 China National Nutrition and Health Survey were included in the study. Information for dietary intake was collected using three consecutive 24-h recalls by trained interviewers. The amounts of cooking oil and condiments consumed were weighed. An interview-administered 1-year physical activity questionnaire was used to collect physical activity information. The results showed that the heavier the parental bodyweight, the higher the overweight prevalence in children. The prevalence ratio increased if parent(s) were overweight and/or obese, up to 12.2 if both parents were obese. Overweight children consumed significantly more dietary energy, protein and fat, but less carbohydrate than their normal weight counterparts. On average, overweight children spent 0.5 h less on moderate/vigorous activities and 2.3 h more on low intensity activities per week. The following prevalence ratios were statistically significant: walking to and from school (0.6); moderate/vigorous activities > or =45 min/d (0.8); low intensity physical activities >2 h/d (1.3); the consumption of > or =25 g/d cooking oil (1.4); > or =200 g/d meat and meat products consumption (1.5); > or =100g/d dairy products (1.8). After adjustment for parental body weight status and socioeconomic status, only cooking oil consumption and walking to and from school remained significantly related to child overweight. In conclusion, parental weight status is an import-ant determinant. Fat intake, low intensity activities and active transport to/from school may be suitable entry points for overweight prevention among Chinese school children.

Phytate intake and molar ratios of phytate to zinc, iron and calcium in the diets of people in China

OBJECTIVE

To assess the phytate intake and molar ratios of phytate to calcium, iron and zinc in the diets of people in China.

DESIGN

2002 China Nationwide Nutrition and Health Survey is a cross-sectional nationwide representative survey on nutrition and health. The information on dietary intakes was collected using consecutive 3 days 24 h recall by trained interviewers.

SUBJECTS

The data of 68 962 residents aged 2-101 years old from 132 counties were analyzed.

RESULTS

The median daily dietary intake of phytate, calcium, iron and zinc were 1186, 338.1, 21.2 and 10.6 mg, respectively. Urban residents consumed less phytate (781 vs 1342 mg/day), more calcium (374.5 vs 324.1 mg/day) and comparable amounts of iron (21.1 vs 21.2 mg/day) and zinc (10.6 vs 10.6 mg/day) than their rural counterparts. A wide variation in phytate intake among residents from six areas was found, ranging from 648 to 1433 mg/day. The median molar ratios of phytate to calcium, iron, zinc and phytate x calcium/zinc were 0.22, 4.88, 11.1 and 89.0, respectively, with a large variation between urban and rural areas. The phytate:zinc molar ratios ranged from 6.2 to 14.2, whereas the phytate x calcium/zinc molar ratios were from 63.7 to 107.2. The proportion of subjects with ratios above the critical values of phytate to iron, phytate to calcium, phytate to zinc and phytate x calcium/zinc were 95.4, 43.7, 23.1 and 8.7%, respectively. All the phytate/mineral ratios of rural residents were higher than that of their urban counterparts.

CONCLUSIONS

The dietary phytate intake of people in China was higher than those in Western developed countries and lower than those in developing countries. Phytate may impair the bioavailability of iron, calcium and zinc in the diets of people in China.

Trends in the distribution of body mass index among Chinese adults, aged 20-45 years (1989-2000)

OBJECTIVE

To describe body mass index (BMI, in kg/m(2)) distribution patterns and trends among Chinese adults, aged 20-45 years (1989-2000).

DESIGN

A descriptive, population-based study of BMI change.

SETTING

Chinese provinces (eight in 1989 and 1997; nine in 2000), representative of the household-based surveys (the China Health and Nutrition Survey, 1989-2000) using multistage, random cluster sampling, supplemented with annual household consumption survey data of the State Statistical Bureau (SSB).

SUBJECTS

A total of 4527, 4507 and 4046 adults, aged 20-45 years, in 1989, 1997 and 2000, respectively.

MEASUREMENTS

BMI (underweight: BMI<18.5 kg/m(2) and overweight: BMI>/=25 kg/m(2)). Percentile curves for BMI in 1989 and 2000 were constructed by gender and age using the LMS (lambda, mu, sigma) method.

RESULTS

Compared with 1989, the 2000 BMI distribution curves flattened at higher levels of BMI (men and women). There was a 13.7% increase in the proportion of men and a 7.9% increase of women who were overweight or obese with a resulting greater change in the annualized prevalence rate for men. This increase in the prevalence of overweight and obesity was far greater than the decrease (2.1% for men; 2.2% for women) in that of underweight. Age-gender-specific percentile curves showed BMI increases mainly among women, aged 35-45 years, and among men at all age groups.

CONCLUSIONS

Chinese BMI dynamics show much greater rates of change among men, aged 20-45 years, than among women, with the increase among women concentrated between ages 35 and 45 years. These changes portend large shifts in other diet-related non-communicable diseases in China over the following decades. Controlling the increasing trends of BMI, especially in men, is an important public health problem facing China.

VAPOR: variance-aware per-pixel optimal resource allocation

Characterizing the video quality seen by an end-user is a critical component of any video transmission system. In packet-based communication systems, such as wireless channels or the Internet, packet delivery is not guaranteed. Therefore, from the point-of-view of the transmitter, the distortion at the receiver is a random variable. Traditional approaches have primarily focused on minimizing the expected value of the end-to-end distortion. This paper explores the benefits of accounting for not only the mean, but also the variance of the end-to-end distortion when allocating limited source and channel resources. By accounting for the variance of the distortion, the proposed approach increases the reliability of the system by making it more likely that what the end-user sees, closely resembles the mean end-to-end distortion calculated at the transmitter. Experimental results demonstrate that variance-aware resource allocation can help limit error propagation and is more robust to channel-mismatch than approaches whose goal is to strictly minimize the expected distortion.

Trends in eating behaviours among Chinese children (1991 -1997)

This study examined the trends in snacking behaviours and eating food-prepared-outside-the-home (FPOH) by Chinese children and adolescents using data from the China Health and Nutrition Survey. The sample consisted of 3223 subjects aged 6-18 in 1991 and 2836 in 1997. Three days of 24hr recall dietary data and per capita income (deflated to 1989) was used. The percentage of Chinese children having snacking behaviours was significantly differentiated according to the income level while percentage of eating FPOH increased in middle and high income groups. Snacking contributed about 8% of the energy intake (EI) for snackers, compared with over 15% from FPOH for those who ate FPOH. Fruit was a major component of snacking: snacks based on fruit intake almost doubled over the study period as did snacks based on soft drink consumption. Animal source food consumption was a key component of FPOH and its intake also increased.

Rate-distortion optimized hybrid error control for real-time packetized video transmission

The problem of application-layer error control for real-time video transmission over packet lossy networks is commonly addressed via joint source-channel coding (JSCC), where source coding and forward error correction (FEC) are jointly designed to compensate for packet losses. In this paper, we consider hybrid application-layer error correction consisting of FEC and retransmissions. The study is carried out in an integrated joint source-channel coding (IJSCC) framework, where error resilient source coding, channel coding, and error concealment are jointly considered in order to achieve the best video delivery quality. We first show the advantage of the proposed IJSCC framework as compared to a sequential JSCC approach, where error resilient source coding and channel coding are not fully integrated. In the USCC framework, we also study the performance of different error control scenarios, such as pure FEC, pure retransmission, and their combination. Pure FEC and application layer retransmissions are shown to each achieve optimal results depending on the packet loss rates and the round-trip time. A hybrid of FEC and retransmissions is shown to outperform each component individually due to its greater flexibility.

[Clinical study on treatment of patients with upper digestive tract malignant tumors of middle and late stage with Ginkgo biloba exocarp polysaccharides capsule preparation]

OBJECTIVE

To observe the clinical efficacy of Ginkgo biloba exocarp polysaccharides (GBEP) capsule preparation in treating upper digestive tract malignant tumors of middle and late stage.

METHODS

Eighty-six patients of the upper digestive tract malignant tumors were treated with GBEP capsule preparation taken orally. The clinical symptoms and the qualities of life of the patients with single GBEP and combined with operation, radiotherapy or intervention chemotherapy were observed. The tumor size was measured by electronic gastroscope before and after treatment with single GBEP. Objective response rate (RR) of the tumor was calculated. The survival period of patient was observed. The changes of blood routine examination in the patients treated with radiotherapy were observed.

RESULTS

GBEP preparation could markedly improve the patients'clinical symptoms. Karnofsky scoring of the patients markedly increased after treatment. There were 2 CR (complete response, 6.3%), 22 PR (partial response, 68.8%)and 5 SD (stable disease, 15.6%) of 32 cases with single GBEP preparation. The survival periods of the 32 cases were markedly prolonged. The preparation could relieve the inhibited hematopietic function and the weight loss due to radiotherapy.

CONCLUSION

GBEP capsule preparation has some definite therapeutic effects on upper digestive tract malignant tumors of middle and late stage.

Therapeutic mechanism of ginkgo biloba exocarp polysaccharides on gastric cancer

AIM: To study the therapeutic mechanism of Ginkgo biloba exocarp polysaccharides (GBEP) on gastric cancer.

METHODS: Thirty patients with gastric cancer were treated with oral GBEP capsules. The area of tumors was measured by electron gastroscope before and after treatment, then the inhibitory and effective rates were calculated. The ultrastructures of tumor cells were examined by transmissional electron microscope. Cell culture, MTT, flow cytometry were performed to observe proliferation, apoptosis and changes of relevant gene expression of human gastric cancer SGC-7901 cells.

RESULTS: Compared with the statement before treatment, GBEP capsules could reduce the area of tumors, and the effective rate was 73.4%. Ultrastructural changes of the cells indicated that GBEP could induce apoptosis and differentiation in tumor cells of patients with gastric cancer. GBEP could inhibit the growth of human gastric cancer SGC-7901 cells following 24-72 h treatment in vitro at 10-320 mg/L, which was dose- and time-dependent. GBEP was able to elevate the apoptosis rate and expression of c-fos gene, but reduce the expression of c-myc and bcl-2 genes also in a dose-dependent manner.

CONCLUSION: The therapeutic mechanism of GBEP on human gastric cancer may relate to its effects on the expression of c-myc, bcl-2 and c-fos genes, which can inhibit proliferation and induce apoptosis and differentiation of tumor cells.

Effect of ambient conditions on the antibacterial activity of antibacterial agent based on sodium titanium phosphate

OBJECTIVE

To investigate the effects of ambient conditions on the antibacterial activity of inorganic antibacterial agent based on sodium titanium phosphate.

METHODS

The number of live E. Coli ATCC 44113 was counted after the suspension was shaken and incubated in flask with antibacterial agent under ambient conditions.

RESULT

The number of live bacteria increased when the concentration of bacteria increased in the range of 1.2 x 10(2) to 1.2 x 10(8) cfu/ml. The antibacterial activity increased with the increase of ambient temperature in the range of 16 approximately 46 degrees C, showing good antibacterial activity at human body temperature. With the increase of the concentrations of co-existing NaCl and protein, the antibacterial activity was found to decrease at first and level off at 0.01 g/ml and 0.0005 g/ml respectively.

CONCLUSION

The antibacterial agent has to be used together with organic antibacterial agent in order to achieve good antibacterial effect when the ambient bacterial concentration is high. The antibacterial agent is promising to be used in the preparation of antibacterial cloth because it is highly effective at body temperature and expected to remain antibacterial in perspiration.

Intrahousehold food distribution: a case study of eight provinces in China

A longitudinal survey of health and nutrition in China was undertaken in eight provinces (Liaoning, Jiangsu, Shandong, Henan, Hubei, Hunan, Guangxi, Guizhou). Data were collected in 1989, 1991, 1993 and 1997. The 1991 and 1993 data were used to investigate factors affecting intrahousehold food distribution. The discrepancy score and the ratio of food share to energy share were used to describe food distribution within households. Findings indicated that, in most cases, males had a higher proportion of nutrient intake than females, particularly in the young adult group where men presented with a higher discrepancy score than women for energy and all nutrients observed. The food and nutrient distribution tends to be more favourable to the middle-aged group, although the youngest group, while accepting relatively smaller amounts of cereals, ate much bigger amounts of meat, dairy products and fruits. Household members with higher incomes are more favoured in terms of food consumption and nutrient intake. Household leaders accepted a higher share of energy and nutrients in comparison with other members of the household across all age and sex groups. Administrators and people working in service or trade industries in rural areas are favoured in terms of food distribution relative to farmers and manual workers. Well-educated people accepted a better food allocation than others and those in employment received more nutrients than the unemployed. The 'contribution rule' (individuals who make a greater contribution to the family receive a larger share of the family's food) is discussed and deemed to be applicable in explaining the discrepancy in food distribution and nutrient intake among household members.

[Distributions of body mass index of Chinese adults]

Based on the Third China National Nutrition Survey conducted in 1992, the distribution of body mass index (BMI) in 44,485 adults aged 20-60 y was analyzed, and the cutoff points of BMI for overweight and obesity were also explored. The results showed that the BMI of Chinese adults was in logarithmic normal distribution. The average BMI of this population was 22.1 +/- 3.1. The 50th, 85th and 95th percentiles of BMI were 21.6, 24.9 and 27.4 kg/m2 respectively. The 85th percentile of BMI was much closer to the BMI cutoff points for overweight recommended by WHO, but the 95th percentile was much lower than WHO's cutoff points for obesity. The distribution of BMI based on age, gender and urban/rural areas was different and with statistical significance. It is considered that age and gender should be taken into account while setting up BMI cutoff points for the overweight and obesity of a population, as well as considering the relationships among BMI and morbidity and mortality, body fat composition, and some blood biochemical indexes.

[Complementary feeding practice in Chinese rural children]

The information of complementary foods consumed by 14649 children aged from 4 to 24 months in poor rural areas was analyzed. On average, it was at 6 months old for children to start complementary feeding. Approximately one third of children started complementary feeding at 4-6 months old and 16.4% children were fed cereal foods before 4 months old. Only 50% of children aged 12 months and above consumed vegetables/fruits daily and 38% of them consumed animal foods. However, 15.8% children never ate animal foods, and 20% children were fed formula milk daily after weaning time. The impact of family dietary pattern on children's diet increased along with the growth of children. It is obvious that the irrational food pattern would undermine growth of children and such diet behavior would eventually result in malnutrition. Poor complementary feeding practice in some selected rural areas in China played a negative role on children's growth. Hence, nutrition education to the mothers and caretaker should be emphasized so that to improve their awareness of the importance of good nutrition practice and guide them to feed weaning children reasonably.

[Transition of dietary pattern in China]

The implications of dietary transition in China during the past 50 years were investigated. Data were collected from the representative national surveys, China Health and Nutrition Survey (1989-1997), China National Nutrition Survey (1982 and 1992), the Annual Household Consumption Surveys of the State Statistic Bureau and the Annual Death Report of China. In the early part of the major economic transformation, cereal intake increased before 1985 and decreased thereafter. There was also a long-term reduction of vegetable consumption, which has stabilized now. Intakes of animal foods increased slowly before 1979 and more quickly after the economic reforms occurred. The total energy intake has reduced, as energy expenditure has, large changes in the composition of energy have occurred. The proportion of energy from fat increased quickly and reached 27.3% in average and 32.8% in urban residents in 1997. More than one third of all Chinese adults and 58.4% of adults in urban areas consuming over 30% of their energy from fat. These changes resulted in rapid increases the prevalence of overweight and obesity and dietary-related chronic non-communicable diseases in urban residents. The traditional Chinese diet is shifting towards a diet with high fat, high energy density and low dietary fiber. The Chinese diets have entered into a new stage of transition.

[A survey on the effects of "Dietary Guideline" nutrition education project]

A survey on the nutrition knowledge, attitude and behavior of 5145 persons from five cities of four provinces, Shandong, Guangdong, Sichuan and Heilongjiang, before and after the nutritional education project on "Dietary Guideline" has been effectively conducted. An obviously good effect has been achieved among the residents, middle and primary school students and elderly people. Before the nutritional educational project has been carried out, the people who understanding the "Dietary Guideline" was only 12.0%, 29.2% and 15.2% of residents, the elderly and students respectively. But after education, the rates raised to 93.4%, 99.0% and 91.9% respectively. Nearly 90% of residents and the elderly got to know the "Dietary Guideline" through the materials distributed from the project. The nutrition knowledge score was improved greatly after the project was conducted. The attitude towards learning nutrition knowledge was good. At the same time, some dietary behavior and the life style of people had been modified. These results indicated that nutrition education is very important on improving people's nutrition knowledge level, changing people's unhealthy living attitudes and dietary habits.

[Radiotherapy for 308 patients with non-small cell lung cancer (NSCLC)]

BACKGROUND

To analyze the survival results retrospectively of the patients with NSCLC treated by radiotherapy alone and the clinical factors affecting the survival results.

METHODS

Three hundred and eight patients with NSCLC from January, 1985 to December, 1991 were included in this study (stage I, 11 cases; stage II, 68 cases; stage IIIA, 155 cases; stage IIIB, 74 cases). All patients were confirmed by pathology and cytology. They were treated by 10 MV-X ray or cobalt-60, conventionally fractionated, with weekly dose 7-11.5 Gy. In 47 patients of them treatment planning system was used at the beginning or in the middle of radiotherapy as to have the primary lesion and mediastinum in the full course of radiotherapy. In the rest of patients whose mediastinal dose was 40Gy by anterior and posterior fields, irradiation dose to the spinal cord was avoided and irradiation dose to the primary lesion got to the definitive treatment. The survival rate was analyzed by Kaplan-Meier and tested by Log-rank.

RESULTS

The median survival was 10 months. The 1-, 3- and 5-year survival rates were 43%, 15% and 9% respectively. The earlier the clinical stage, the better the prognosis (P=0.0001). The survival rate of the patients with complete remission at the end of radiotherapy was better than that of the patients with residual tumor (P=0.0001). The survival of the patients with weekly dose larger than 10 Gy was better ( P=0.0461). There was no relationship among the survival rate and the total dose and mediastinal dose.

CONCLUSIONS

The results show the survival rate of patient with NSCLC treated by radiotherapy alone was related to clinical stage, instant response and weekly dose, but not to the total dose and the mediastinal dose.

Current methods for estimating dietary iron bioavailability do not work in China

Three current equations for estimating iron bioavailability were evaluated, and adjustments were proposed that would allow us to most effectively study iron bioavailability in China. Dietary intake data were obtained from 24-h dietary recalls taken over three consecutive days as part of the third Chinese National Nutrition Survey. Hemoglobin status was measured for 42,606 Chinese adults aged 18-60 y. The mean iron intake was 24.4 mg per capita per day, which was 177% of the Chinese RDA (209% of U.S. RDA). About 18% of the sample was classified as being anemic, indicating a large iron deficiency anemia and iron bioavailability problem in China. A number of methods proposed by World Health Organization and U.S. scholars were examined for adjusting iron bioavailability. Even the methods that consider several iron enhancers and inhibitors did not work adequately for the Chinese diet. The statistical assessment of the fit between iron bioavailability and hemoglobin status provided direction for adjusting the best of these predictive equations. We propose a new predictive approach for iron bioavailability which is more predictive of Chinese iron status. Consideration of additional dietary elements such as rice and bean consumption patterns are important. Our findings provide insight into additional factors which may influence iron bioavailability as well as possible improved methods for estimating the combined effect of multiple dietary factors on iron bioavailability, particularly in a vegetarian diet.

[Dietary intake of some micronutrients in different provinces of China]

Based on the data collected in 1992 China National Nutrition Survey, which covered 100,201 persons of all ages in 29 provinces, the dietary intakes of some micronutrients were calculated. The intake of calcium, retinal equivalent and riboflavin were the most insufficient nutrients; zinc, selenium and thiamin were close to (80%-90%) of Chinese RDAs. The intakes of niacin, ascorbic acid and vitamin E were sufficient. The regions in the northeast, northwestern and the southeastern inland were more at risk of nutrition deficiency. Dietary intervention or food fortification with some micronutrients could be used for improving the situation.

Sex difference in measures of body fatness and the possible difference in the effect of dietary fat on body fatness in men and women

OBJECTIVES

To examine the sex difference in anthropometric measures of body fatness and to explore the possibility that diet may have differential effects on body fatness in men and women.

DESIGN

Prospective study design.

SETTING

The first and second China Health and Nutrition Survey conducted in 1989 and 1991, respectively.

SUBJECTS

1449 men and 1683 women age 20-35 y at the baseline (1989) survey.

METHODS

Anthropometric measures of body fatness in men and women were compared. Statistical methods were used to explore the potential difference in the effect of dietary fat on body fatness in men and women.

RESULTS

Measures of body fatness, especially peripheral fatness, differed markedly between men and women in this study sample. Statistical analysis suggested that the effect of dietary fat on body fatness may be different in men compared to women.

CONCLUSIONS

Sexual dimorphism in body fatness has important implications for both clinical and epidemiologic research of obesity. The possibility that diet may have differential effect on body fatness in men and women needs to be investigated.

[Effect of nutrition on the health improvement of preschool children in rural areas]

"Surveillance and Improvement of Children's Nutrition" is the largest project in connection with the nutrition of preschool children in China up to now. It focused on nutrition improvement of preschool children in rural areas. The results of the baseline survey and the project final evaluation surveys showed that the nutritional status of children was improved from 1990 to 1995. The prevalence of moderate and severe stunting and underweight at the national level decreased by 23.1% and 28.6% respectively. Anemia decreased by 48%. It was identified that the benefits of nutrition improvement were associated with nutrition education and other integrated nutrition interventions, e.g., improvement the dietary habit of the target children.

Food price policy can favorably alter macronutrient intake in China

The rapid change in diets, physical activity and body composition in low income countries has led to the coexistence of large pockets of undernutrition and overnutrition. Public health strategies for addressing this situation may be necessary, and price policy options are examined for China. Longitudinal dietary data collected in China in 1989-1993 on a sample of 5625 adults aged 20-45 y were examined. Three-day averages of food group consumption and nutrient intake were used in longitudinal statistical models to examine separately the effects of food prices on the decision to consume each food group and then the amount consumed. The effects of changes in six food prices on the consumption of each of six food groups, not just the food group whose price had changed, and on three macronutrients were estimated. The effects show large and significant price effects. If the joint effects of the nutrition transition are to be considered, then there are clear tradeoffs among which foods to tax and which to subsidize. Most important is the effect of prices in reducing fat intake of the rich but not adversely affecting protein intake for the poor. Increases in the prices of pork, eggs and edible oils are predicted to lower fat intake. Only increases in pork prices led to reduced protein intakes. This raises questions about earlier policy changes being implemented in China and provides insight into an important and controversial area for public health policy.

[Impact of maternal occupation on the dietary and nutritional status of preschool children. A case study in 8 provinces of China]

This analysis is based on the data from China Health and Nutrition Survey (undertaken in 8 provinces of China from 1989 to 1998) in collaboration with the University of North Carolina at Chapel Hill. Totally, 1461 and 1087 mother-child pairs under age 6 were selected to investigate the impact of maternal occupation on the dietary and nutritional status of children in 1991 and 1993. The results show that the nutrients intake and nutritional status of children whose mothers worked in administrative, scientific, technological and other professional units were better than any other groups. The status of children whose mothers were workers, waiters etc. in factories or service sectors was better than that of children whose mothers were farmers or self-employed laborers. The children of non-working mothers were better nourished than the children whose mothers were farmers, or self-employed laborers, but were more undernourished than the children whose mothers worked in administrative, scientific, technological and other professional units. The associations among maternal occupation, income and education level of mothers were significant. Mothers working in administrative, scientific, technological units etc. had higher yearly income and education level than other groups. But the income and education level of farmers and self-employed laborers were the lowest. The time allocation of mothers was also studied and the results suggested that maternal occupation affected the time spent for child care and food preparing.

[Studies on the factors affecting the individual's animal protein intake by a multi-level model]

In this article, the influence of factors related to different levels (seg, provincial, county and household) on the proportion of protein intake from animal food was evaluated by using multi-level modeling. It was found that after being adjusted by individual factors, the factors related to the household, such as household income, dietary habit and knowledge of nutrition were the most important factors affecting the individual's showed animal protein intake. In addition, the results showed that the difference of animal protein intake in various places depended not only on the increase of household income, but also dietary behavior and agriculture crops in different areas. Comparison of different models indicates that in analyzing the data from large-scale health survey with hierchical structure, multi-level modeling is strongly recommended.