Diet and Nutrition Survey of Infants and Young Children in Scotland, 2011

Chapter 4 Physical measurements

Summary of findings

• Boys and girls in the Diet and Nutrition Survey of Infants and Young Children in Scotland (DNSIYCS) were, in general, taller (longer), heavier and had larger head circumferences than the UK World Health Organization (UK-WHO) Growth Standard for their age and sex.
• At age 4 to 11 months, both boys and girls in DNSIYCS were significantly taller (longer) than those in the DNSIYC UK sample. Girls in the Scottish sample also had significantly greater average weight and head circumference measurements across the age groups than the UK sample.

4.1. Introduction

Results in this chapter are presented by age at the Computer Assisted Personal Interview (CAPI) interview. Weight, length and head circumference measurements were taken. The small numbers in the individual age groups should be borne in mind when interpreting results, particularly when examining percentages beyond the outer centiles.

Revised UK World Health Organisation (UK-WHO) growth charts for birth to two years were introduced for all new births in Scotland from January 2010. These are based on UK-WHO Growth Standards from data in infants who were exclusively or predominantly breastfed^[1],[2]. Predominantly formula fed children are on average larger for their age compared to predominantly breastfed children on which these standards are based.

In Chapter 4, all comparisons to the main Diet and Nutrition Survey of Infants and Young Children (DNSIYC) UK sample were tested at the 95% significance level. Statistically significant differences are highlighted in the text.

4.2. Results

4.2.1 Length, weight and head circumference

Of the 616 fully productive children, valid length and head circumference was achieved for 92%, and weight for 97% of these children. According to standard practice, a measurement was deemed invalid if either a) the derived sex- and age-adjusted UK-WHO Z-score^[3] was below -6 or above +6 or b) in the opinion of the interviewer, the measurement taken was unreliable.

The mean length of all boys in the Diet and Nutrition Survey of Infants and Young Children in Scotland (DNSIYCS) was 77.0cm; that is 73.9cm for those aged 4 to 11 months and 80.5cm for those aged 12 to 18 months. When compared with the UK‑WHO Growth Standard for their age and sex, 81% of boys aged 4 to 11 months and 68% aged 12 to 18 months were above the 50^th percentile.

The mean length for all girls was 75.9cm. For those aged 4 to 11 months mean length was 72.5cm and 79.5cm for those aged 12 to 18 months. The proportion of girls in DNSIYCS above the 50^th percentile for length was 79% of girls aged 4 to 11 months and 67% of girls aged 12 to 18 months.

For all boys in DNSIYCS the mean weight was 10.3kg. For those aged 4 to 11 months the mean weight was 9.5kg and 11.2kg for boys aged 12 to 18 months. When compared with the UK-WHO Growth Standard for their age and sex, 76% of all boys were above the 50^th percentile; that is 76% of boys aged 4 to 11 months and 77% of boys aged 12 to 18 months.

For all girls the mean weight was 9.9kg. For those aged 4 to 11 months the mean weight was 9.0kg and 10.8kg for 12 to 18 months. The proportion of all girls in DNSIYCS above the 50^th percentile for weight was 81%; 81% of those aged 4 to 11 months and 83% of those aged 12 to 18 months.

For all boys in DNSIYCS the mean head circumference was 47.1cm; that is 46.3cm for those aged 4 to 11 months and 48.0cm for children aged 12 to 18 months. When compared with the UK-WHO Growth Standard for their age and sex, 83% of all boys were above the 50^th percentile. For each age group the percentage of boys above the 50^th percentile was at least 80%.

For all girls in DNSIYCS the mean head circumference was 46.1cm, that is 45.1cm for those aged 4 to 11 months and 47.1cm for 12 to 18 months. When compared with the UK-WHO Growth Standard for their age and sex, 85% of all girls were above the 50^th percentile for head circumference; at least 84% across each age group.

As shown in Table 4.1, more than 50% of children within the DNSIYCS sample exceeded the 50^th percentiles for growth compared to the UK-WHO growth standard for their age and sex. This might be partially explained by the predominance of formula feeding by this group at the time of the survey, while the growth standards are based on exclusively or predominantly breastfed children.

Table 4.1

4.2.2 Comparisons between the Scotland and the DNSIYC UK samples

When compared statistically to the entire DNSIYC UK sample, at age 4 to 11 months boys in Scotland had a significantly larger average length (73.9cm) than the UK sample (73.3cm). There were no other significant differences in physical measurements between boys in Scotland and the UK.

Girls aged 4 to 11 months in Scotland had a significantly larger average length (72.5cm) than the UK sample (71.5cm). Girls in Scotland aged 4 to 11 months (9.0 kg) were significantly heavier than girls in the UK (8.7kg), as were girls aged 12 to 18 months (10.8kg in Scotland compared to 10.6kg in the UK sample). Girls in Scotland aged 4 to 11 months had a significantly larger average head circumference (45.1cm) than girls of the same age in the UK (44.6cm) as did girls aged 12 to 18 months (47.1cm in Scotland compared to 46.8cm in the UK sample).

Table 4.2