Guangzhou Nutrition and Health Study (GNHS)

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Description

Purpose: The Guangzhou Nutrition and Health Study (GNHS) aims to assess the determinants of risk of osteoporosis and cardio-metabolic diseases and changes in their relevant indices (e.g., osteoporosis, atherosclerosis, type 2 diabetes, hypertension, metabolic syndrome, non-alcoholic fatty liver dise...

Purpose: The Guangzhou Nutrition and Health Study (GNHS) aims to assess the determinants of risk of osteoporosis and cardio-metabolic diseases and changes in their relevant indices (e.g., osteoporosis, atherosclerosis, type 2 diabetes, hypertension, metabolic syndrome, non-alcoholic fatty liver disease, cardiovascular diseases, chronic kidney disease, body composition, etc.) in nutritional aspects, as well as other environmental and genetic factors. Study design: GNHS is a community-based prospective cohort study. Participants: About 4048 apparently healthy residents, living in Guangzhou city (South China) for >5 years, aged 40-80 years, recruited between 2008 and 2013. Visits and Data Collection: Participants were/will be visited every three years by invited to the School of Public Health, Sun Yat-sen University. At each visit, face-to-face interviews, specimen collection, anthropometric measurements, DXA scanning, ultrasonography evaluation were/will be conducted. Up to May 2017, 3143 subjects completed their 2nd visits, and 2312 attended their 3rd visits. It is planned to follow up the participant in person for at least 15 years. Key variables: Questionnaire interviews: Structured questionnaires were/will be used to collect the participants' socio-demographic characteristics (e.g., age, sex and household income), lifestyle factors (smoking, passive smoking, alcohol drinking, tea drinking, physical activity), menstruation and reproductive history (women only), sleep quality (Pittsburgh Sleep Quality Index, PSQI), family history, psychological health (Self-Rating Anxiety Scale, SAS), social support and participation, cognitive function (Mini-Mental State Examinations, MMSE), habitual dietary intake (a validated 79-item quantitative food frequency questionnaire), use of supplements and history of chronic diseases. Physical examinations: Anthropometric measurements (weight, height, waist, hip and neck circumference, etc.), blood pressure tests, handgrip strength, and usual gait speed. DXA scanning: A dual-energy x-ray absorptiometry (DXA, Discovery W; Hologic Inc.) was/will be used to determine bone density and bone mineral content at the whole body, lumbar spine (L1-L4), left hip sites, bone geometry information at the hip, fat mass and muscle mass at total body and its sub-regions. Ultrasonography evaluations: Ultrasonography evaluation of the carotid artery and upper abdominal organs (e.g., liver and kidney) was/will be performed to determine carotid artery intima-media thickness and plaque, fatty liver. Specimen collections: Overnight fasting blood sample was/will be collected and separated into serum, plasma, erythrocyte and leukocyte within two hours. Early morning first-void urine sample and faces samples were/will be collected. All specimens were/will separated and stored at -80°C till tests. Laboratory tests: Metabolic syndrome-related indices: Fasting serum lipid profile, diabetes-related indices, uric acid and creatinine; Nutritional indices: Serum concentrations of carotenoids, erythrocyte fatty acids, serum minerals, folate, betaine, choline, TMAO, and vitamin D, etc. Inflammatory markers (e.g., CRP, RBP4?IL-6, TNF-a) Sexual hormones, SHBG Genetic markers Urinary tests: Flavonoids and flavones, minerals, creatinine and renal function related markers Fecal test: Gut microbiota and related metabolites. Morbidity and mortality: Relevant data were/will be also retrieved via local multiple Health information systems. Others: Many other laboratory tests or instrument tests will be developed depended on needs and resources in future. Data analysis: Analyses of variance and covariance, or mixed effects model were/will be used to compare the mean differences in continuous outcomes (e.g., changes of bone mineral density, body fat mass, or intima-media thickness) among the quartiles. Cox proportional hazards or logistic regression models were/will be used to assess the risk of exposures (e.g., nutrition intakes and physical activity) on categorical outcomes. Path analysis was/will be used to assess the potential mediating effects in the causal pathway between exposures and outcomes.

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