1 in 6 adolescent girls in Hong Kong iron-deficient

A cross-sectional study of 523 adolescents finds a 17.1 percent and 10.9 percent prevalence of iron deficiency (ID) and ID with anaemia (IDA), respectively, among girls in Hong Kong.

Adolescents are at high risk of developing ID as the body’s demand for iron increases during puberty and rapid growth, yet it may not be met due to inadequate dietary iron intake and can be further impacted by chronic menstrual blood loss in girls. [Mol Asp Med 2020;doi:10.1016/j.mam.2020.100861]

Healthy adolescents (age range, 16–19 years; mean age, 17.6 years; girls, 65.0 percent) from 16 public secondary schools were recruited through blood donation campaigns run by the Red Cross Blood Transfusion Service. Approximately 10 mL of blood was collected from each participant under fed conditions, as they were advised to have adequate food and fluid intake before blood donation. [Int J Environ Res Public Health 2023;doi:10.3390/ijerph20032578]

Mean haemoglobin (Hb) level in the overall cohort was 13.25 g/dL, while mean serum ferritin was 94.6 μg/L. In total, 58 adolescents (11.1 percent) had serum ferritin levels of <15 μg/L and were considered to have ID. All of them were female, resulting in an ID prevalence of 17.1 percent among girls.

In the overall cohort, the rate of IDA was 7.1 percent based on the WHO definition (Hb level <12 g/dL in girls and <13 g/dL in boys) and 4.4 percent based on the local definition (Hb level <11.5 g/dL in girls and <12 g/dL in boys). Seven boys had Hb levels of 12.2–12.9 g/dL and were classified as anaemic according to WHO’s definition. Subsequent thalassaemia genotyping conducted on six of the seven boys revealed that three of them had alpha-thalassemia trait and three had beta-thalassemia trait.

Among girls with Hb levels <12 g/dL, 37 (10.9 percent) had IDA according to WHO’s definition. Of the 20 girls with IDA who underwent thalassaemia trait genotyping, only three had alpha-thalassaemia trait, while 17 others were negative for either alpha- or beta-thalassaemia trait.

Of female participants, 14.8 percent reported heavy or very heavy menstrual bleeding, which was significantly associated with lower serum ferritin levels (p=0.028).

When asked about their dietary patterns, 36.3 percent of participants (females, 40.6 percent; males, 28.4 percent) reported a regular habit of skipping at least one meal a day. Meal skipping was related to suboptimal iron intake. Participants who skipped at least one meal a day had lower serum ferritin levels vs participants who did not (p=0.017). Interestingly, in multivariable analyses, lower serum ferritin levels were also found in participants who skipped breakfast (p=0.019) or lunch (p=0.011), but not dinner (p=0.66).

“Breakfast was the most commonly skipped meal [28.5 percent], which is worrying, as breakfast provides a unique opportunity to consume important micronutrients that may be less present in other meals of the day, particularly vitamins and minerals,” noted the researchers.

After adjusting for age and sex, lower serum ferritin levels were significantly correlated with poorer health-related quality of life in terms of physical (p=0.0047) and school functioning (p=0.045), and general fatigue (p=0.016). Similarly, participants who often skipped at least one meal a day reported poorer physical functioning (p=0.0017), emotional functioning (p=0.026) and school functioning (p=0.027), while those with lower dietary iron intake also reported poorer physical functioning (p=0.0014) and school functioning (p=0.010).

“Our findings suggest that it would be beneficial to promote public health initiatives that emphasize healthy dietary habits among adolescent girls and promote awareness of the health consequences of menstrual disorders. This will encourage affected girls to seek medical attention before the anaemic symptoms manifest as functional impairments,” concluded the researchers.