20% of (2nd to 8th graders enrolled in school) showed indications / diagnoses of asthma. Source: Norway's Asthma and Allergy Association (NAAF). Nordlandsstudien (1995-2009 p: 6000)
5% of children require medical treatment for asthma (estimate).
25-30% of youths have allergic symptoms.
Source: the Norwegian Institute of Public Health
The total number of people living with asthma in Ireland is 470,000. 1 in 5 of that population are children, counting to 94,000. The data comes from the Asthma Society of Ireland's website, but there is no reference to which year these data were collected and how.
In a cross‐sectional study conducted in rural Senegal (Niakhar), Hooper et al. found that nearly one in ten children had symptoms suggestive of asthma; however, few children had a diagnosis of asthma or use appropriate therapies. More specifically, from a total of 1513 children aged 6‐7 years, 130 (9%) reported wheezing within the last 12months, and 41 (3%) had a clinical asthma diagnosis.
Methodology: The researchers used the International Study of Asthma and Allergies in Childhood (ISAAC) survey instrument to assess childhood respiratory health in rural Senegal. They interviewed the caregivers of children aged 5 through 8 years of age in the four largest Niakhar villages in August 2012.
The astma rates in Germany are around 5% to 8,6%.
I found only one study that had studied childhood asthma rates in/around Dar es Salaam. The data was found in an article published in 2014. The study was done with high school students. In this study, they had chosen two sites: one in Ilala (close to the city centre, urban environment) and one in Bagamoyo (located about 1,5 hours from Dar es Salaam.
The overall asthma rate was: 11.8%. Comparison between the two sites revealed that pupils in Ilala district had a higher asthma rate (17.1%) than in Bagamoyo (6,6%)
There seem to be no studies done on a national level that measure the percentage of asthma in children. The only other studies I found online comparative study between Tanzania and Cameroon from 2004 (Source: https://www.ncbi.nlm.nih.gov/pubmed/15510944). The most recent study is from 2019 in a paper that assess under five mortality rates that name asthma as being a significant contributor (www.journalajpas.com/index.php/AJPAS/article/download/28788/54094/)
Children (0-17 years old) with asthma (J45-J46) in 2012: 21267 children (13467 of them are male children and 7800 - female children).
Also in this file: Dinamics of number of children with asthma 2001-2011 (for 100 000 inhabitants) (Liet. Vaikų (0-17m.) sergamumo ir ligotumo astma dinamika 2001-2011 m., (rodiklis 100 000 gyv.)) [there is a scheme, but i cant copy it here].
But the numbers of children with asthma have rised almost 3 times! From 977,0 in 2001 to 3393,6 in 2011
Source: "VAIKŲ IR JAUNIMO SVEIKATOS STEBĖSENA LIETUVOJE", Šarūnas Alasauskas, Higienos institutas, Sveikatos informacijos centras, Biostatistinės analizės skyrius, email@example.com, https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=2ah...
Authors of the research: Institute of the hygiene, Health information centre, Department of Biostatistic analysis
8-10% of children of school-age (in Sweden this is 7-16 years old) have asthma according to Barnallergisektionen.
A document from the Kenya Ministry of Public Health and Sanitation on guidelines for asthma management estimates that between 10% and 18% of children 13-14 years of age in Kenya have asthma. This is from the ISAAC phase 1 and 3 study, but was only conducted in two sites, Eldoret and Nairobi.