Excess Weight, Dietary Habits and Vitamin D and Omega-3 Fatty Acid Status in Pregnancy

The aim of the study is to investigate excess weight prevalence, related dietary habits, physical activity, and fatty acids, including omega-3 fatty acid and vitamin D status in pregnant women in Latvia. The main tasks are to investigate excess weight prevalence before pregnancy and gestational weight gain; to investigate dietary patterns, physical activity, omega-3 and D vitamin intake and blood level in pregnant women and to evaluate association between excess weight, dietary patterns, physical activity and omega-3 fatty acid and vitamin D statuses during pregnancy. A cross-sectional study between July 2020 and January 2023. The target group were pregnant women and women until 7th day post-partum, and the representative sample was formed by stratified sampling (stratified according to region and level of urbanization, Central Statistical Bureau of Latvia (CSB),2019). Exclusion criteria were: age less than 18 years; multiple pregnancies; place of residence outside Latvia during pregnancy; history of or present health disorders — diabetes, celiac disease, short bowel syndrome, Crohn's disease, ulcerative colitis and history of eating disorders. Informed consent was signed by respondents before enrolment. Respondents will be given a unique code to provide their anonymity. Data was collected from medical documentation and by direct face-to-face interviews in maternity departments in hospitals and in outpatient clinics in various regions of Latvia. The questionnaire consisted of the following parts: demographic data, anthropometric data, self-assessment of nutritional habits, daily physical activities and emotional well-being(n=837)and data from medical documentation(“mothers pasport”): anthropometric data, blood tests etc. Additional tests were done for assessing level of vitamin D, parathormone (PTH) and fatty acids, including omega 3 fatty acids. Blood test were collected from the antecubital vein by specialist of accredited laboratory Twenty tree fatty acids have been determined in erythrocyte phospholipids by GC-FID method. Vitamin D (25 hydroxyvitamin D: 25 (OH) D) in serum ((n=816) and PTH has been determined by chemiluminescent microparticle immunoassay (CMIA) method, Alinity System (Abbott) method ( with reference limits for adults (1.48 - 7.63 pmol/L)). Twenty tree fatty acids have been determined in erythrocyte phospholipids by gas chromatography GC-FID method. at the accredited laboratory "BIOR Dietary data obtained using FFQ and food diary were sent to the Institute of Food Safety, Animal Health and Environment (BIOR) for processing. The food frequency questionnaire (n=856) about the participants' diet during the last six months (frequency and quantity of 211 food products) was adapted from the questionnaire of insturute "BIOR" for obtaining nutritional data on the population of Latvia. Pregnant women also filling 7-day food diary (n=125). Respondents was received written and oral instructions about how correctly to fill food diary. Food scales were used for estimation of portion size.

本研究旨在调查拉脱维亚孕妇的超重患病率、相关饮食习惯、体力活动情况，以及脂肪酸（包括Omega-3脂肪酸）与维生素D的营养状态。本研究的核心任务包括：调查孕前超重患病率与妊娠期体重增长情况；探究孕妇的饮食模式、体力活动、Omega-3与维生素D的摄入情况及血液水平；并评估妊娠期超重、饮食模式、体力活动与Omega-3脂肪酸及维生素D状态之间的关联。本研究为2020年7月至2023年1月期间开展的横断面研究。研究目标人群为孕妇及产后7天内的女性，代表性样本采用分层抽样方法构建（分层依据为地区与城市化水平，数据来源为拉脱维亚中央统计局（Central Statistical Bureau of Latvia, CSB）2019年统计资料）。排除标准如下：年龄未满18周岁；多胎妊娠；妊娠期间居住地位于拉脱维亚境外；患有或既往存在糖尿病、乳糜泻、短肠综合征、克罗恩病、溃疡性结肠炎等健康问题，以及进食障碍病史。研究对象在入组前需签署知情同意书，并将被分配唯一编码以保障其匿名性。研究数据通过两种方式采集：一是查阅医疗档案，二是在拉脱维亚各地区医院产科病房及门诊诊所开展面对面访谈。调查问卷包含以下模块：人口统计学资料、人体测量学数据、饮食习惯自评、日常体力活动及情绪健康状况（有效样本量n=837），以及来自产妇档案手册（"mothers pasport"）的数据：人体测量学指标、血液检测结果等。额外开展的检测项目包括维生素D、甲状旁腺激素（parathormone, PTH）及脂肪酸（包括Omega-3脂肪酸）水平测定。血液样本由认证实验室的专业人员通过肘前静脉采集。研究采用气相色谱-火焰离子化检测法（GC-FID）测定了红细胞磷脂中的23种脂肪酸。血清维生素D（25-羟维生素D：25(OH)D，有效样本量n=816）及甲状旁腺激素的检测采用化学发光微粒免疫分析法（CMIA），使用雅培Alinity系统完成，成人参考范围为1.48~7.63 pmol/L。另有提及，红细胞磷脂中的23种脂肪酸亦采用气相色谱-火焰离子化检测法（GC-FID）完成测定。在认证实验室"BIOR"处，通过食物频率问卷（Food Frequency Questionnaire, FFQ）及食物日记获取的膳食数据将被提交至食品安全、动物健康与环境研究所（BIOR）进行数据处理。本研究使用的食物频率问卷（FFQ，有效样本量n=856）改编自BIOR研究所针对拉脱维亚人群营养数据采集研发的问卷，该问卷用于调查研究对象近6个月的膳食摄入情况（涵盖211种食物的摄入频率与食用量）。此外，共有125名孕妇填写了为期7天的食物日记。研究对象会收到书面及口头指导，以掌握正确填写食物日记的方法。研究采用食物秤对食物分量进行估算。