Table 2. Studies focusing on micronutrients.

Authors (y)	Objective (s)	Study design	Settings	Sample	Age	Sex	Exposure (s)	Outcomes (s)	Main findings
Desalegn D, 2014 [74]	To determine the prevalence, severity, and predictors of nutritional IDA	Cross sectional study	Urban	586 (269 aged 10–12)	10–12	M/F	-	Iron deficiency anemia (Hb <12 g/dl)	Iron deficiency anemia 32.7%
Wakao T, 2015 [70]	To determined vitamin D deficiency and its predictors	Cross sectional study	Urban/rural	174	11–18	M/F	Age, sex, parental education, wealth index	vitamin D deficiency (25(OH)D <50 nmol/L)	Vitamin D deficiency was 42% (girls 51.5%, boys 29.3%). Females (AOR = 1.76; 95% CI: 0.8, 3.8), older adolescent (AOR = 1.4; 95% CI: 0.7, 3.1) and urban residence (AOR = 10.5; 95% CI: 3.9, 28.2) are at higher risk of Vitamin D deficiency.
DHS report, 2016 [75]	To assess adolescent nutrition, including anaemia	Repeated cross-sectional survey	Urban/rural	-	15–19	M/F	Sex and setting	Anemia ((Hb <12 g/dl)	Anemia: urban girls 16.7%, rural girls 20.4%, Urban boys (8.6%), rural boys (20.4%). Anemia trends: in girls 15–19 years: 2005 (23.6; severe 1.0, moderate 12.7, mild 9.8), 2011 (13.3; severe 1.0, moderate 4.7%, mild 7.5%), 2016 (19.6; severe 0.9%, moderate 7.3%, mild 11.4%). Anemia trend: in boys 15–19 years: 2011: 17.7% (0.4% Severe, 2.4 moderate and 14.9 mild), 2016 18.2% (severe 0.1%, moderate 3.6%, and mild 14.4%).
Ministry of Health, 2016 [69]	Ethiopia National Micronutrient Survey to estimate the prevalence of selected micronutrient (Iron, Folate, vitamin A, Retinol, Zinc, Iodine, Vitamin B12) deficiencies	Cross-sectional study	Urban/rural	722	12–19 years	M/F	Age	Anemia, level of vitamin A, Vitamin B12, deficiencies of Zinc, iodine, folate	Anemia ((Hb <12 g/dL):14.9% (moderate (Hb 8–12 g/dL14.4%, severe (Hb<8g/dL 0.5%) in age of 12–14 years and 11.8% (10.5% moderate and 1.3% severe) in age 15–19 years. Iron deficiency (Ferritin<15) was 8.6%. Iron deficiency anemia (Ferritin) was 2.6% and (STFR) was 4.3% in age 12–14 years. Mean (SD) Vitamin A status was 1.20±0.35 and % (Retinol <0.7 μmol/l) was 6.3% in age 12–14 years. Iron deficiency (Ferritin<15) was 10.0%, (STFR<4.4) 83.8%, and IDA (Ferritin) 3.2%, IDA (serum transforming receptor) was 4.7%, vitamin A mean value 1.40±0.43, and % (Retinol <0.7 μmol/l) was 3.2% in age 15–19 years. Deficiencies: Zinc 38%, Iodine 1.88% for severe deficiency (<20μg/L), 25.2% for moderate deficiency (50–99.9 μg/L) and 20.5% for mild deficiency (20–49.9 μg/L). Excess iodine (>300 μg/L) 12.2% in age group 12–14 years. Deficiencies: Serum folate (<6.8nmol/L) 14.7%, Vitamin B12 (<203 pg/ml) 13.6%, iodine (Severe deficiency(<20 μg/L) 1.9%, moderate deficiency (50–99.9 μg/L) 28.6%, mild deficiency (20–49.9 μg/L) 21.9%, and Excess (>300 μg/L) 7.9% in age group 15–19 years.
Teji K, 2016 [39]	To assess the prevalence of anaemia and nutritional status of adolescent girls	Cross-sectional study	Urban/rural	547	10–19	F	-	Anemia ((Hb <12 g/dl)	Anemia 32% (HGB<12), severe 1.8% (HGB<7), moderate 3.8% (HGB 7–9.9), and mild 26.3% (HGB 10–11.9)
Getaneh Z, 2017 [68]	To assess the prevalence and associated factors of anemia	Cross-sectional	Urban	523 (332 aged 11–14)	11–14)	M/F	-	Anemia (Hb <12 g/dl)	Anemia 13.4%
Workie S, 2017 [67]	To assess the prevalence of iodine deficiency disorder	Cross-sectional study	Urban/rural	718	10–20+	M/F	Age, sex, setting, use of iodized salt	Iodine deficiency disorder (as measured by thyroid gland Enlargement)	Goiter 48.9% (boys 35.1%, girls 65.2%). Grade-1 goiter 36.9% and Grade-2 goiter 11.9%. Goiter is associated positively with girls (AOR = 3.5; 95%CI: 2.6–4.9) and negatively with regular use of iodized salt (AOR = 0.5; 95%CI: 0.3–0.7)
Gonete K, 2017 [71]	To assessed the prevalence and associated factors of anemia	Cross-sectional study	Urban/rural	462	15–19	F	Setting, dietary diversity, household food insecurity, source of water	Anemia (Hb <12 g/dl)	Overall anemia was 25.5%, (95% CI: 21.4, 29.2) with mild anemia 92.4%, moderate 5.9% and severe 1.7% Odds of having anemia among those with inadequate DDS was 2.1 higher (AOR = 2.1; 95% CI: 1.3, 3.5).
Wakayo T, 2018 [73]	To evaluate the association between Serum Vitamin D levels of 25(OH)D and handgrip strength	Cross-sectional study	Urban/rural	174	11–18	F	-	Serum Vitamin D level	Average serum 25(OH)D was 54.5 + 15.8 nmol/L.
Seyoum Y, 2019 [72]	To determine the prevalence of iron deficiency, low iron stores, and anemia and characterize selected risk factors	Cross-sectional study	Rural	257	15–19	F	-	Anemia (Hb <11 g/dl)	Anemia 8.7% (Hb <11 g/dL) and clinical iron deficiency 8.7% (Serum Ferretin <15 μg/L), but 41% had marginal iron stores (SF <50 μg/L).
Mengistu G 2019 [77]	To assess the prevalence of anemia and associated factors	Cross sectional	Urban	423	10–19	F	Age, DDS, family zise, family income,	Iron deficiency anemia (Hb <12 g/dl)	Anemia 11.1%. Predictors are: family size>5 [AOR = 3.2, 95%CI: 1.3–7.9), lower average family income (AOR = 10; 95%CI; 2.5–41.3).
Demelash S 2019 [78]	To assess the prevalence of anemia and its associated factors	Cross-sectional study	Urban	594	15–19	F	-	Anemia (Hb<12 g/dl)	Anemia prevalence 21.1% (CI: 17.4, 24).
Gebreyesus SH 2019 [79]	To evaluate the prevalence of anaemia	Cross sectional study	Urban/rural	1323	10–19	F	Age, residency, food insecurity	Anemia (Hb< 12.0 g/dl)	Anemia 28.8% (Urban 31.6%, rural19%) Anemia predictors: Younger (10–14 years) adolescent (AOR = 2.0; 95% CI: 1.1, 3.8)
Regasa RT, 2019 [80]	To determine the status of anemia and its anthropometric, dietary and socio demographic determinants	Cross-sectional study	Urban/rural	448	10–19	F	Age, residency, family size, parental education family wealth status, DDS,	Anemia (Hb< 12.0 g/dl, mild (10–11.9 g\dl), moderate (7.0–9.9 g/dl,) or severe (<7 g\dl)	Anemia 27% (95% CI: 22.9–31%, mild 23% and moderate 4%) Associated factors: age (younger 10–14 years 38.6%, older age 15–19 years 12.6%, p-value <0.05), settings (rural 45.3%, urban 12.5%, p-value <0.05)
Gebremichael G, 2020 [76]	To investigate the prevalence of goiter and associated factors	Cross-sectional study	Urban/rural	576	10–19	M/F	Sex, age, family history of goiter, residence, use of iodized salt, DDS, altitude	Goiter	Goiter 42.5% (95% CI: 38.4%, 46.7%; boys 34%, girls 50.9%) Goiter predictors: Being female (AOR = 1.8; 95% CI: 1.2, 2.9), family history of goiter (AOR = 3.6; 95% CI: 2.3, 5.7), lack of meat consumption (AOR = 2.5; 95% CI: 1.2, 5.3), lack of milk consumption (AOR = 2.2; 95% CI: 1.2, 4.0), and inadequate use of iodized salt (AOR = 7.1; 95% CI: 3.8, 12.9)