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.

[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.

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.

[Prevalence and risk factors of perivascular space in the population of Shunyi Study].

Objective: To investigate the prevalence on imaging, topographic distribution and risk factors of perivascular space (PVS) in community population. Methods: This study was based on the population of Shunyi Study in China from June 2013 to September 2016. One thousand two hundred and thirty-two stroke free participants older than 35 years, who completed cerebral MRI, were included. Cardiovascular risk factors were assessed by interview, physical examination and blood sample tests. PVS were evaluated on high-resolution 3-dimensional-T1WI, T2WI and FLAIR sequences. On T1WI, PVS were detected according to 3D imaging criteria. The number and anatomic location of large PVS (≥3 mm) were recorded. And severity of PVS was then semiquantitatively graded in both white matter (WM) and basal ganglia (BG). Associations between risk factors and PVS were analyzed by multinominal Logistic regression models and adjusted for age, gender and relevant confounders. Results: Perivascular spaces were observed in the BG or WM in every subject, aged (55±10) years and 37.3% male. Large PVS were detected in 19.0% (460/1 232) of participants. Severity of PVS was found to be strongly associated with age in both basal ganglia (severe versus mild: OR=1.81; 95%CI 1.45-2.27, P<0.01) and white matter (OR=1.39; 95%CI 1.13-1.71, P<0.01), and the proportion of subjects with hypercholesterolemia decreased with the severity of PVS in BG (OR=0.58, P=0.01) . The present of large PVS was found to be associated with age(present versus absent: OR=1.03, 95%CI 1.02-1.05, P<0.01) and ApoE ε4 carrier genotype(OR=1.53, 95%CI 1.01-2.23, P=0.04). Conclusions: Perivascular spaces are always detected in the BG or WM in elderly people, and large PVS are also prevalent in community-based population. The risk factors are different due to distribution and size, and may depend on anatomic or pathologic characteristics.

Quantum Spin Hall Effect and Tunable Spin Transport in As-Graphane.

Tunable spin transport in nanodevices is highly desirable to spintronics. Here, we predict existence of quantum spin Hall effects and tunable spin transport in As-graphane, based on first-principle density functional theory and tight binding calculations. Monolayer As-graphane is constituted by using As adsorbing on graphane with honeycomb H vacancies. Owing to the surface strain, monolayer As-graphane nanoribbons will self-bend toward the graphane side. The naturally curved As-graphane nanoribbons then exhibit unique spin transport properties, distinctively different from the flat ones, which is a two-dimensional topological insulator. Under external stress, one can realize tunable spin transport in curved As-graphane nanoribon arrays. Such intriguing mechanical bending induced spin flips can offer promising applications in the future nanospintronics devices.

[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.

[Blood cerebrospinal fluid barrier damage of rats induced by lead acetate or nano-lead exposure].

OBJECTIVE: To investigate the damage of blood-cerebrospinal fluid barrier (BCB) of rats induced by lead and nano-lead exposure in order to provide the basis for mechanism study of lead neurotoxicity. METHODS: 39 male rats were randomly divided into control group, lead acetate exposed group and nano-lead exposed group. Rats in lead acetate exposed group and nano-lead exposed group were given 20 mg/kg lead acetate or nano-lead by oral gavage and rats in control groups were given the same amount saline for 9 weeks.Morris maze was used to test the learning function, serum albumin and CSF albumin were determined by ELISA. Confocal laser scanning microscope was applied to detect ZO-1 and Occludin protein expression in choroid plexus, real time-PCR was used to test the expression of ZO-1 and Occludin mRNA expression. Pathological changes of choroid plexus cells were observed by the electron microscopy. RESULTS: Compared with the control group, the escape latency of rats in lead acetate or nano-lead exposure group were longer and times of across platform were less. The levels of CSF albumin and the CSF albumin index in lead acetate or nano-lead exposed rats were obviously higher, and the fluorescence intensity of ZO-1, Occludin as well as mRNA expressions were lower than those in control group(P<0.05). Compared with lead acetate exposed group, the levels of CSF albumin and the CSF albumin index in nano-lead exposure group were higher. The fluorescence intensity and mRNA expressions of ZO-1, Occludin in nano-lead exposure group were than those in lead acetate group(P<0.05). Electron microscopy revealed that lead acetate or nano-lead exposure could induce shorter microvillus of choroid plexus epithelial cells, mitochondrion destruction and partial disconnection in intracellular junctions between two adjacent epithelial cells. CONCLUSION: Lead acetate and nano-lead exposed can result in the blood-cerebrospinal fluid barrier damage, which may involve in the process of lead induced neurotoxicity. Meanwhile, nano-lead exposure can induced in more worse damage in terms of blood-results in blood-cerebrospinal fluid barrier function.

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.

Risk factors for hearing loss in neonates admitted to neonatal intensive care units.

OBJECTIVE: This study aimed to research risk factors of hearing loss among neonates in the neonatal intensive care unit. METHOD: Hearing screening tests were performed on 572 neonates in the neonatal intensive care unit. Those who failed screening tests were referred for diagnostic tests. RESULTS: The pass rates for automated auditory brainstem response, distortion product otoacoustic emission and acoustic impedance tests at first hearing screening were 69.93 per cent, 70.02 per cent and 92.92 per cent for 1144 ears. Failure in the first screening correlated with preterm birth, very low birth weight, revised advanced maternal age, neonatal hyperbilirubinaemia and Activity, Pulse, Grimace, Appearance, Respiration score less than 8. Thirty cases failed in diagnostic hearing tests for brainstem auditory evoked potentials, 28 failed in otoacoustic emissions and 33 failed in acoustic impedance, which correlated with preterm birth, very low birth weight, twins, advanced maternal age and revised advanced maternal age. CONCLUSION: Abnormalities in the hearing levels of most neonates who needed hearing retests were completely or partially reversible. Preterm birth, very low birth weight, twins and advanced maternal age are potential risk factors for hearing impairment.

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.

Cerebral Microbleeds Are Associated with Loss of White Matter Integrity.

BACKGROUND AND PURPOSE: Previous studies have shown that diffusion tensor imaging suggests a diffuse loss of white matter integrity in people with white matter hyperintensities or lacunes. The purpose of this study was to investigate whether the presence of cerebral microbleeds and their distribution are related to the integrity of white matter microstructures. MATERIALS AND METHODS: The study comprised 982 participants who underwent brain MR imaging to determine microbleed status. The cross-sectional relation between microbleeds and the microstructural integrity of the white matter was assessed by 2 statistical methods: a multilinear regression model based on the average DTI parameters of normal-appearing white matter and Tract-Based Spatial Statistics analysis, a tract-based voxelwise analysis. Fiber tractography was used to spatially describe the microstructural abnormalities along WM tracts containing a cerebral microbleed. RESULTS: The presence of cerebral microbleeds was associated with lower mean fractional anisotropy and higher mean diffusivity, axial diffusivity, and radial diffusivity, and the association remained when cardiovascular risk factors and cerebral small-vessel disease markers were further adjusted. Tract-Based Spatial Statistics analysis indicated strictly lobar cerebral microbleeds associated with lower fractional anisotropy, higher mean diffusivity, and higher radial diffusivity in the internal capsule and corpus callosum after adjusting other cerebral small-vessel disease markers, while only a few voxels remained associated with deep cerebral microbleeds. Diffusion abnormalities gradients along WM tracts containing a cerebral microbleed were not found in fiber tractography analysis. CONCLUSIONS: Cerebral microbleeds are associated with widely distributed changes in white matter, despite their focal appearance on SWI.

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.

Application of pyrite and chalcopyrite as sensor electrode for amperometric detection and measurement of hydrogen peroxide.

The sensing performance of solid-state amperometric sensors based on natural sulfide minerals, i.e., pyrite and chalcopyrite, has been characterized for the detection and measurement of hydrogen peroxide (H2O2) in aqueous medium. The sensors showed a wide linear relationship range between response current and the concentration of H2O2 from 1.0 × 10-5 mol L-1 to 1.0 × 10-2 mol L-1 and 1.0 × 10-4 mol L-1 to 3.0 × 10-2 mol L-1 for pyrite and chalcopyrite, respectively. The limit of detection (LOD) was as low as 8.6 × 10-6 mol L-1 and 5.2 × 10-5 mol L-1 (S/N = 3), respectively. The electrodes exhibited great sensitivity, repeatability and short response time (less than 5 s). The results show that pyrite and chalcopyrite can be used as a natural, low cost, reliable and sensitive sensor for hydrogen peroxide detection, creating a new and high value application for the sulfide minerals.

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.

Secular trends in meat and seafood consumption patterns among Chinese adults, 1991-2011.

BACKGROUND/OBJECTIVES: Several studies have suggested differential health effects in relation to different meat composition in Western population. The purpose of the study was to examine secular trends in meat and seafood consumption patterns among Chinese adults between 1991 and 2011. SUBJECTS/METHODS: Our longitudinal data are from 21,144 adults aged 18-75 in the China Health and Nutrition Survey, prospective cohort study. We assessed the intakes of meat and subtypes with three 24-h dietary recalls. We conducted multilevel mixed-effect logistic and linear regression models to examine meat consumption dynamics. RESULTS: The proportions of Chinese adults who consumed red meat, poultry and seafood increased from 65.7% in 1991 to 86.1% in 2011, from 7.5 to 20.9% and from 27.4 to 37.8%, respectively. With rapid decrease in meat intakes since 2009, the intakes of total meat, red meat, poultry and seafood among their consumers were 86.7 g/day, 86.4 g/day, 71.0 g/day and 70.3 g/day in 2011, respectively, which were just slightly higher compared with those in 1991. Fatty fresh pork has been predominantly component of total meat overtime, which consituted 54.0% of total meat intake, 80.0% of fresh red meat intake and 98.7% of fatty fresh red meat intake in 2011. CONCLUSION: Over the past two decades, meat consumption patterns of Chinese adults have been characterized by having a predominant intake of fatty fresh pork, suboptimal intakes of seafood and increased proportion of adults having excessive intakes of red meat and poultry overtime.

Landau levels and magneto-transport property of monolayer phosphorene.

We investigate theoretically the Landau levels (LLs) and magneto-transport properties of phosphorene under a perpendicular magnetic field within the framework of the effective k·p Hamiltonian and tight-binding (TB) model. At low field regime, we find that the LLs linearly depend both on the LL index n and magnetic field B, which is similar with that of conventional semiconductor two-dimensional electron gas. The Landau splittings of conduction and valence band are different and the wavefunctions corresponding to the LLs are strongly anisotropic due to the different anisotropic effective masses. An analytical expression for the LLs in low energy regime is obtained via solving the decoupled Hamiltonian, which agrees well with the numerical calculations. At high magnetic regime, a self-similar Hofstadter butterfly (HB) spectrum is obtained by using the TB model. The HB spectrum is consistent with the LL fan calculated from the effective k·p theory in a wide regime of magnetic fields. We find the LLs of phosphorene nanoribbon depend strongly on the ribbon orientation due to the anisotropic hopping parameters. The Hall and the longitudinal conductances (resistances) clearly reveal the structure of LLs.

Dietary patterns and their associations with general obesity and abdominal obesity among young Chinese women.

BACKGROUND/OBJECTIVES: Dietary patterns represent the combined effects of foods and efficaciously illustrate the impact of diet on health outcomes. This study identified the dietary patterns and determined their relationships with obesity among young Chinese women. SUBJECTS/METHODS: In 2011, the China Health and Nutrition Survey included 2363 young women aged 18-44 years. Factor analysis of data from three consecutive 24-h dietary recalls identified the dietary patterns. Weight, height and waist circumstance (WC) were measured, and body mass index (BMI) was calculated. General obesity was defined as BMI ⩾28 kg/m(2) and abdominal obesity as WC ⩾85 cm. RESULTS: Four dietary patterns were identified: traditional south; traditional north; snack; and high protein. After adjusting for confounders and energy intake, women in the highest-score quintiles of the traditional south pattern were less likely to have general obesity (odds ratio (OR)=0.48; 95% confidence interval (CI) 0.29-0.78) and abdominal obesity (OR=0.64; 95% CI 0.46-0.90). Subjects in the highest-score quintiles of the traditional north pattern had significantly greater risk of general obesity (OR=2.28; 95% CI 1.38-3.74) and of abdominal obesity (OR=2.32; 95% CI 1.66-3.24). CONCLUSION: The traditional south pattern of rice as the major staple food with pork and vegetable dishes is associated with lower risk of general and abdominal obesity. The traditional north pattern of high intake of wheat, other cereals and tubers is positively associated with general and abdominal obesity. This provides important information for interventions and policies addressing obesity prevention among young Chinese women.

Effect of nationality on dietary pattern and meal behavior in China.

In 1992 a national nutrition survey was conducted in China in approximately 100,000 people of all ages selected with use of a multistage, stratified, random, clustered procedure. Dietary data were collected with three consecutive 24-h recalls. A total of 9304 members of 20 minority nationality groups were included in the survey, accounting for 9.3% of the total sample. Meal behavior varied greatly according to nationality. Almost all Koreans and Tibetans ate three meals daily but 85% of Lahu people ate only two. Members of many other groups, including the Han, the majority nationality group in China, ate between two and three meals a day. People who ate two meals a day usually ate less than did those consuming three meals. The minority groups consumed amounts of dietary energy and protein comparable to those eaten by the majority group, although cereals accounted for a larger portion and animal food a smaller portion of energy and protein intakes. There were no differences in the dietary patterns of men and women of the same nationalities.

The nutritional status and dietary pattern of Chinese adolescents, 1991 and 1993.

OBJECTIVE: To increase understanding about current dietary patterns and short-term relationships between economic change and adolescent nutrition in a lower-income country, using the 1991 and 1993 China Health and Nutrition Survey data. DESIGN: Cross-sectional study. SETTING: Eight provinces in China that vary substantially in geography, economic development, public resources, and health indicators. SUBJECTS: 2236 and 2018 adolescents aged 10-18 years who completed three 24-hour recalls in the 1991 and 1993 survey, respectively. RESULTS: Chinese adolescents experienced an improvement of diet and nutritional status. The prevalence of stunting declined from 23% in 1991 to 19% in 1993. Under-nutrition was a problem of concern although the prevalence (12-13%) was relatively low. Overweight was emerging as a problem associated with young, high-income and urban adolescents, but the prevalence (4%) was quite low compared with developed countries. Chinese adolescents' energy and protein intakes were adequate compared with the American RDA. About 27% of the participants derived more than 30% of their dietary energy from fat and 16% of them derived over 10% of energy from saturated fat by 1993. CONCLUSION: Chinese adolescents have experienced an improvement in diet and nutritional status, but undernutrition is still an important nutrition problem, especially among young and poor groups. More attention should focus on the increase of dietary fat intake and obesity.