Dietary sodium intake and overweight and obesity in children and adults: a protocol for a systematic review and meta-analysis

Systematic Reviews, Jan 2016

Background Overweight and obesity in children and adults is a major public health concern. Emerging evidence suggests dietary sodium intake may be associated with obesity. This systematic review and meta-analysis will aim to (i) assess the relation between dietary sodium intake and measures of adiposity in children and adults and (ii) examine the relation between sodium intake and sugar-sweetened beverage (SSB) consumption, which is a known risk factor for obesity. Methods/design An electronic search will be conducted using Medline Complete, CINAHL, Scopus, Embase and Cochrane central register of controlled trials (CENTRAL). The search strategy will identify published peer-reviewed articles that report on dietary sodium and either a marker of adiposity or SSB consumption. Only human studies (ages >1 year) in English will be included, and no limits will be placed on publication date. No restrictions will be placed on the method of sodium intake assessment. Cross-sectional, prospective studies, and randomised controlled trials with a duration of ≥3 months will be included. Studies with participants with renal disease, cancer, type 1 diabetes or heart failure or who are pregnant will be excluded. To assess the quality of studies, the Cochrane’s Collaboration tool for assessing risk of bias in randomised trials will be used for randomised controlled trials (RCTs), and the modified Newcastle-Ottawa Scale will be used for cross-sectional and prospective studies. Meta-analysis will be used to assess the relation of sodium intake with two primary outcomes: (i) BMI and body weight in adults and BMI z-score in children and (ii) weight category (i.e. healthy weight vs. overweight/obese). For any outcomes in which meta-analysis is not possible, we will present data as a systematic review. Findings will be grouped and reported separately for children and adolescents (ages 1–17 years) and adults (ages >18 years). Discussion This review and meta-analysis will provide insight into the relation between dietary sodium intake and overweight and obesity. This information can be used to inform public health policies which target population sodium consumption. Systematic review registration Prospero CRD42015016440

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Dietary sodium intake and overweight and obesity in children and adults: a protocol for a systematic review and meta-analysis

Grimes et al. Systematic Reviews Dietary sodium intake and overweight and obesity in children and adults: a protocol for a systematic review and meta-analysis Carley A. Grimes 0 Dieuwerke P. Bolhuis 2 Feng J. He 1 Caryl A. Nowson 3 0 Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University , 221 Burwood Highway, Burwood, Victoria 3125 , Australia 1 Centre for Environmental and Preventative Medicine, Wolfson Institute of Preventative Medicine, Queen Mary University of London , Charterhouse Square, London EC1M 6BQ , UK 2 Centre for Advanced Sensory Science, School of Exercise and Nutrition Sciences, Deakin University , 221 Burwood Highway, Burwood, Victoria 3125 , Australia 3 Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University , 75 Pigdons Road, Waurn Ponds Campus, Geelong, Victoria 3216 , Australia Background: Overweight and obesity in children and adults is a major public health concern. Emerging evidence suggests dietary sodium intake may be associated with obesity. This systematic review and meta-analysis will aim to (i) assess the relation between dietary sodium intake and measures of adiposity in children and adults and (ii) examine the relation between sodium intake and sugar-sweetened beverage (SSB) consumption, which is a known risk factor for obesity. Methods/design: An electronic search will be conducted using Medline Complete, CINAHL, Scopus, Embase and Cochrane central register of controlled trials (CENTRAL). The search strategy will identify published peer-reviewed articles that report on dietary sodium and either a marker of adiposity or SSB consumption. Only human studies (ages >1 year) in English will be included, and no limits will be placed on publication date. No restrictions will be placed on the method of sodium intake assessment. Cross-sectional, prospective studies, and randomised controlled trials with a duration of ≥3 months will be included. Studies with participants with renal disease, cancer, type 1 diabetes or heart failure or who are pregnant will be excluded. To assess the quality of studies, the Cochrane's Collaboration tool for assessing risk of bias in randomised trials will be used for randomised controlled trials (RCTs), and the modified Newcastle-Ottawa Scale will be used for cross-sectional and prospective studies. Meta-analysis will be used to assess the relation of sodium intake with two primary outcomes: (i) BMI and body weight in adults and BMI z-score in children and (ii) weight category (i.e. healthy weight vs. overweight/obese). For any outcomes in which meta-analysis is not possible, we will present data as a systematic review. Findings will be grouped and reported separately for children and adolescents (ages 1-17 years) and adults (ages >18 years). Discussion: This review and meta-analysis will provide insight into the relation between dietary sodium intake and overweight and obesity. This information can be used to inform public health policies which target population sodium consumption. Systematic review registration: Prospero CRD42015016440 Dietary salt; Dietary sodium; Sodium chloride; Adiposity; Obesity; Body mass index; Body weight; Sugarsweetened beverage Background In many countries, overweight and obesity in children and adults is a major public health issue [ 1 ]. The consequences of obesity are substantial and include adverse health and psychological outcomes and increased economic burden [ 2 ]. The accumulation of excess weight during childhood is particularly concerning as it promotes the early onset of chronic diseases, such as cardiovascular disease and diabetes [ 3 ], and increases the risk of being overweight and obese in adulthood [ 4 ]. Whilst the causes of obesity are complex and multifactorial, an overall unhealthy diet characterised by excess energy is considered to be the cornerstone for excess weight gain [ 5, 6 ]. Recently, a number of studies have emerged which suggest that dietary sodium intake may be implicated in weight gain. Studies in children [ 7–9 ] and adults [ 8, 10–12 ] have reported positive associations between sodium intake and a range of adiposity outcomes including BMI or in the case of children BMI z-score, weight category, percent body fat and abdominal obesity. Cross-sectional studies conducted in children from the UK, USA and Australia have shown dietary sodium intake is positively associated with the consumption of energy-rich sugar-sweetened beverages [ 13–15 ]. It has been postulated that this relationship may be due to the effects of sodium on thirst, as experimental studies in both animals and humans show increased fluid intake on a higher sodium diet [ 16, 17 ]. Reported associations between sodium intake and adiposity outcomes may be confounded by energy intake, as foods high in sodium are often also high in energy. However, it may also be the case that energy intake (...truncated)


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Carley Grimes, Dieuwerke Bolhuis, Feng He, Caryl Nowson. Dietary sodium intake and overweight and obesity in children and adults: a protocol for a systematic review and meta-analysis, Systematic Reviews, 2016, pp. 7, 5, DOI: 10.1186/s13643-015-0175-3