DESIGN: We analysed data of children who participated in the Health Survey for England from 1997 to 2016 (n=34 235). This repeated cross-sectional survey reported weight loss attempts and sociodemographic characteristics. Body weight and height were measured by trained interviewers, and body mass index for age z-score was calculated. Multivariable logistic regression was used to investigate the sociodemographic determinants.
SETTING: England.
PARTICIPANTS: Children (8-17 years).
MAIN OUTCOME MEASURES: Weight loss attempts by year, age group, gender, BMI for age z-score, ethnicity and household income.
RESULTS: The prevalence of reported weight loss attempts increased significantly from 21.4% (1997-1998) to 26.5% (2015-2016). The increase was significant for boys, older children, Asian children, children from lower income households and in all categories of BMI for age z-score. Significant predictors of weight loss attempts included having overweight (8-12 years old, OR 4.01 (%CI 3.47 to 4.64); 13-17 years old, OR 1.96 (%CI 1.58 to 2.42)) or obesity (8-12 years old, OR 13.57 (%CI 11.94 to 15.43); 13-17 years old, OR 4.72 (%CI 3.94 to 5.66)) as well as being older, girls, from ethnic minority groups or low household income.
CONCLUSION: The prevalence of reported weight loss attempts among children is increasing at a faster rate than the rise in excess weight and includes an increasing proportion of children with a 'healthy' weight. The increase in the prevalence of reported weight loss attempts among children is greatest among subgroups with lower baseline prevalence.
METHODS: In this experiment, a new adequate ternary mixture liquid for preparation of BMF applied and suspended with a new scatter particle material, this scatter particle material called poly (4-methylstyrene), it used to be adequate with the mixture density and for saving neutrally buoyant. This BMF was prepared for use in the test objects or Doppler flow phantom. The poly (4-methylstyrene) particles were applied for suspension in a mixture liquid or fluid based on three items, which were distilled water, propylene glycol (PG), and polyethylene glycol (PEG) (200 Mw). The diameter of poly (4-methylstyrene) particles is 3-8 μm, which determined by specific sieve in a unit of μm, and the density is 1.040 g/ml.
RESULTS: Speed of sound, viscosity, density, Backscatter power and attenuation features of mixture fluid or liquid which used for preparing a BMF were measured, discussed, and agreed with draft International Electrotechnical Commission values.
CONCLUSIONS: There are three various types of ternary items of mixture fluid (water, PG, and PEG [200 Mw]), and a new type of scatter particle material poly (4-methylstyrene) was utilized for preparing the BMF. The scatter particles and mixture fluid prepared and measured at a temperature that simulates the body temperature 37°C. Moreover, one of the advantages of this new blood that is being cheaper than the commercially available BMF products because the PG and the polyethylene glycol (200 Mw) are much cheaper and more available than glycerol and the Dextran that used usually. In addition, new BMF needs less time for preparation compared to the commercial one.