Person:

Yuan, Changzheng

Background: Relatively little is known about the peer influence in health behaviors within university dormitory rooms. Moreover, in China, the problem of unhealthy behaviors among university students has not yet been sufficiently recognized. We thus investigated health behavior peer influence in Peking University dormitories utilizing a randomized cluster-assignment design. Methods: Study design: Cross-sectional in-dormitory survey. Study population: Current students from Peking University Health Science Center from April to June, 2009. Measurement: Self-reported questionnaire on health behaviors: physical activity (including bicycling), dietary intake and tobacco use. Results: Use of bicycle, moderate-intensity exercise, frequency of sweet food and soybean milk intake, frequency of roasted/baked/toasted food intake were behaviors significantly or marginally significantly affected by peer influence. Conclusion: Health behavior peer effects exist within dormitory rooms among university students. This could provide guidance on room assignment, or inform intervention programs. Examining these may demand attention from university administrators and policy makers.

Purpose To investigate associations between serum 25-hydroxyvitamin D levels and dry eye syndrome (DES), and to evaluate the differential effect of vitamin D on ocular diseases including age-related macular disease (AMD), diabetic retinopathy (DR), cataract, and DES. Methods: A total of 16,396 participants aged >19 years were randomly selected from the Korean National Health and Nutrition Examination Survey. All participants participated in standardized interviews, blood 25-hydroxyvitamin D level evaluations, and comprehensive ophthalmic examinations. DES was defined by a history of clinical diagnosis of dry eyes by a physician. The association between vitamin D and DES was compared to the associations between vitamin D and AMD, DR, cataract, and DES from our previous studies. Results: The odds of DES non-significantly decreased as the quintiles of serum 25-hydroxyvitamin D levels increased (quintile 5 versus 1, OR = 0.85, 95%CI: 0.55–1.30, P for trend = 0.076) after adjusting for potential confounders including age, sex, hypertension, diabetes, smoking status, and sunlight exposure times. The relative odds of DES (OR = 0.70, 95% CI: 0.30–1.64) and cataract (OR = 0.76, 95% CI: 0.59–0.99) were relatively high, while those of DR (OR = 0.37, 95% CI: 0.18–0.76) and late AMD (OR = 0.32, 95% CI: 0.12–0.81) were lower in men. Conclusions: The present study does not support an association between serum 25-hydroxyvitamin D levels and DES. The preventive effect of serum 25-hydroxyvitamin D may be more effective for DR and late AMD than it is for cataract and DES.

Nutritional factors have been intensively studied as important determinants of many diseases. Food frequency questionnaires (FFQ), dietary records, 24-hour dietary recalls, nutrient biomarkers are important dietary assessment methods, and are subject to various sources of measurement error. Given the limitations of these methods, much effort has been devoted to refining them and evaluating their ability to measure diet. This dissertation focused on evaluating the performance of a semi-quantitative FFQ (SFFQ), multiple web-based automated-self-administered 24-hour recalls (ASA24), 7-day dietary records (7DDR) and biochemical indicators in assessing nutrient intakes among women. Intraclass correlation coefficient, Spearman correlation coefficient, and validity coefficient calculated by method of triads were used to evaluate the reproducibility and validity of each dietary method.

The first paper evaluated the performance of a 152-item SFFQ comparing intakes of nutrients estimated by SFFQ with those measured by the average of two 7DDR, and of four ASA24s kept over a one-year period. The study SFFQ performed consistently well when compared with multiple diet records, and that modifications to the questionnaire over time have adequately taken into account the changes in the food supply and eating patterns that have occurred since 1980. Multiple ASA24s can provide similar estimates of validity as dietary records if day-to-day variation is taken into account.

The second paper explored the validity of long-term intakes of energy, protein, sodium and potassium assessed by SFFQ and ASA24s using recovery biomarkers and 7DDR as standards. The study SFFQ and averaged ASA24’s are reasonably valid measurements for energy-adjusted protein, sodium and potassium compared to multiple recovery biomarkers or dietary records. Recovery biomarkers should not be considered to be without error, including systematic within-person error.

Finally, the third paper further evaluated the validity of nutrient assessed by SFFQ and ASA24 compared with intakes by the 7DDR and plasma levels of fatty acids, carotenoids, retinol, tocopherols and folate. Again, the study SFFQ provides reasonably valid measurements for specific fatty acid, most carotenoids, alpha-tocopherol and folate compared to concentration biomarkers or dietary records. Compared to SFFQ, almost all nutrients estimated by averaged ASA24s had relatively low correlations with biomarkers, 7DDRs and estimated ‘true’ underlying intakes.

Introduction: Expectant mothers in low-income and middle-income countries often lack access to vital information about pregnancy, preparation for birth and best practices when caring for their newborn. Innovative solutions are needed to bridge this knowledge gap and dramatically improve maternal and neonatal health in these settings. This study aims to evaluate the impact of an innovative text messaging intervention on maternal and neonatal health outcomes. Methods and analysis This study offers expectant mothers in rural China a package of free short messages via cell phone regarding pregnancy and childbirth. These messages are tailored to each mother's gestational week. It is hypothesised that delivering these short advice messages to pregnant women can improve maternal and newborn health. The study uses factorial quasi-randomisation to compare psychological, behavioural and health outcomes between 4 groups: 2 groups receiving different sets of short message interventions (ie, good household prenatal practices and healthcare seeking), a group receiving both interventions and a control group. Treatment assignment occurs at the individual level. The primary outcome is newborn health, measured by appropriateness of weight for gestational age. Secondary outcomes include severe neonatal and maternal morbidity as well as psychological and behavioural measures. This study has enrolled pregnant women who attend county maternal and child health centres for their prenatal visits. Discussion This pilot is the first large-scale effort to build a comprehensive evidence base on the impact of prenatal text messages via cell phone on maternal and newborn health outcomes in China. The study has broad implications for public health policy in China and the implementation of mobile health interventions in low-resource settings around the world. Ethics This study was approved by the Ethics Committee of the School of Medicine at Xi'an Jiaotong University on 18 January 2013. Trial registration number NCT02037087; Pre-results.

China has a historic system of wide cycle tracks, many of which are now encroached by cars, buses and bus stops. Even with these conditions, college students still bicycle. On campuses, students park their bikes on facilities ranging from kick-stand-plazas to caged sheds with racks, pumps and an attendant. In other countries, including Canada, some of the newer cycle tracks need to be wider to accommodate an increasing number of bicyclists. Other countries will also need to improve their bike parking, which includes garage-basement cages and two-tiered racks. China could provide lessons about cycle tracks and bike parking. This study applied the Maslow Transportation Level of Service (LOS) theory, i.e., for cycle tracks and bike parking, only after the basic needs of safety and security are met for both vehicle occupants and bicyclists can the higher needs of convenience and comfort be met. With random clustering, a self-administered questionnaire was collected from 410 students in six dormitory buildings at Peking University in Beijing and an environmental scan of bicycle parking conducted in school/office and living areas. Cycle tracks (1 = very safe/5 = very unsafe) shared with moving cars were most unsafe (mean = 4.6), followed by sharing with parked cars (4.1) or bus stop users (4.1) (p < 0.001). Close to half thought campus bike parking lacked order. The most suggested parking facilities were sheds, security (guard or camera), bicycle racks and bicycle parking services (pumps, etc.). If parking were improved, three quarters indicated they would bicycle more. While caged sheds were preferred, in living areas with 1597 parked bikes, caged sheds were only 74.4% occupied. For the future of China’s wide cycle tracks, perhaps a fence-separated bus lane beside a cycle track might be considered or, with China’s recent increase in bike riding, shared bikes and E-bikes, perhaps cars/buses could be banned from the wide cycle tracks. In other countries, a widened cycle track entrance should deter cars. Everywhere, bike parking sheds could be built and redesigned with painted lines to offer more space and order, similar to car parking.

Background: In women, adhering to an overall healthy lifestyle is associated with a dramatically reduced risk of cardio-metabolic disorders. Whether such a healthy lifestyle exerts an intergenerational effects on child health deserves examination.

Methods: We included 5,701 children (9-14 years old at baseline) of the Growing Up Today Study 2, and their mothers, who are participants in the Nurses' Health Study II. Pre-pregnancy healthy lifestyle was defined as a normal body mass index, no-smoking, physical activity ≥150min/week, and diet in the top 40% of the Alternative Healthy Eating Index–2010. Obesity during childhood and adolescence was defined using the International Obesity Task Force age- and sex-specific cutoffs. Multivariable log-binominal regression models with generalized estimating equations were used to evaluate the association of pre-pregnancy healthy lifestyle and offspring obesity.

Results: We identified 520 (9.1%) offspring who became obese during follow-up. A healthy body weight of mothers and no smoking before pregnancy were significantly associated with a lower risk of obesity among offspring: the relative risks [RRs; 95% confidence intervals (CIs)] were 0.37 (0.31-0.43) and 0.64 (0.49-0.84), respectively. Eating a healthy diet and regular moderate-to-vigorous physical activities were inversely related to offspring obesity risk, but these relations were not statistically significant. Compared to children of mothers who did not meet any low-risk lifestyle factors, offspring of women who adhered to all four healthy lifestyle factors had 75% lower risk of obesity (RR 0.25, 95%CI 0.14-0.43).

Conclusion: Adherence to an overall healthy lifestyle before pregnancy is strongly associated with a low risk of offspring obesity in childhood, adolescence, and early adulthood. These findings highlight the importance of an overall healthy lifestyle before pregnancy as a potential strategy to prevent obesity in future generations.