Characteristics of 30 included systematic reviews for adult-onset asthma, ranked by Joanna Briggs Institute (JBI) score
| Authors | Risk factor(s) | Main findings | Adult-onset asthma# | JBI score |
| Romero Starke et al. [20] | Occupational exposure to cleaning and disinfection agents | Nurses exposed to cleaning products to have an increased risk of asthma. | Yes | 11 |
| Yu et al. [21] | Formaldehyde exposure | A significantly increased risk of asthma in adults with high concentrations of formaldehyde exposure was found. | Unclear | 11 |
| Wang et al. [22] | Exposure to greenness | The results are contradictory, with all three included studies showing different associations. | Unclear | 10 |
| Chen et al. [23] | Zinc and selenium levels | The meta-analysis provides evidence that lower circulating Zn and Se levels are associated with an increased risk of asthma. | Unclear | 10 |
| Etminan et al. [24] | Acetaminophen use | The results are consistent with an increase in the risk of asthma in adults exposed to acetaminophen. | Unclear | 10 |
| Zhang et al. [25] | Organic dust exposure | The meta-analysis found organic dust exposure to be a risk factor for asthma. | No | 9 |
| Shen et al. [26] | Early life vitamin D deficiency | No statistically significant association between early life vitamin D deficiency and asthma development later in life was found. | Unclear | 9 |
| Nurmatov et al. [27] | Volatile organic compounds | The results of the effect on volatile organic compounds on the development of asthma are inconsistent. | Unclear | 9 |
| Sharpe et al. [28] | Exposure to indoor fungi | Exposure to certain species of fungi might increase the risk of developing asthma. | Unclear | 9 |
| Mu et al. [29] | Birth weight | The results suggest that low birth weight (<2500 g) is associated with increased risk of asthma both in children in adults, but high birth weight (>4000 g) was not associated with increased risk of asthma. | Unclear | 9 |
| Macan et al. [30] | Persulphates | Persulphates were associated with asthma in hairdressers, in particular bleaching products. | Yes | 8 |
| Sio et al. [31] | Wide range | The study showed housing related factors such as mould, male sex, smoke exposure and BMI-related factors to be associated with asthma. | Mixed | 8 |
| Rodriguez et al. [32] | Urban–rural differences | The findings provide evidence that urban residence and urbanisation are important determinants of asthma. | Unclear | 8 |
| Cong et al. [33] | Temperature changes | There was no increased risk for asthma development in adults when temperature dropped. | No | 8 |
| Wiggans et al. [34] | Wood dust | Work in this sector was associated with a significantly increased risk of respiratory symptoms and asthma. | Unclear | 8 |
| Uphoff et al. [35] | Socioeconomic position | Low socioeconomic position was found to be associated with asthma risk. | Unclear | 8 |
| Tan et al. [36] | Risk factors associated with age of onset | Adults with late-onset current asthma are more likely to be female (58–75%), smokers (56%). | Yes | 8 |
| Lieberoth et al. [37] | Age at menarche | Early menarche (<12 years) appears to be associated with increased risk of asthma. | Unclear | 8 |
| Kakutani et al. [38] | Arachidonic acid intake | The results suggest that arachidonic acid exposure is not consistently associated with asthma risk. | Mixed | 8 |
| Takkouche et al. [39] | Exposure to furry pets | In adults, the evidence regarding either an increased or decreased risk of asthma when exposed to furry pets is inconclusive. | Unclear | 8 |
| Beuther et al. [40] | BMI | Higher BMI is associated with developing asthma. | Yes | 8 |
| Jaakkola et al. [41] | Pre-term delivery | Premature babies seem to have an increased risk of developing asthma later in life, but the results in adults are inconclusive. | Unclear | 8 |
| Mikkelsen et al. [42] | Wide range | A higher BMI and early puberty increase asthma risk. Lifetime smoking, alcohol consumption, late puberty and linoleic acid seem to be protective factors. Vitamin B12, iron and folate intake are not significant. | Yes | 7 |
| Canova et al. [43] | Domestic paints | The variable quality of the exposure assignment makes it difficult to draw firm conclusions on whether there is an association. | Unclear | 7 |
| Baur et al. [44] | Workplace irritants | There is evidence that long-term exposure to workplace irritants could increase asthma development. | Unclear | 7 |
| Flaherman et al. [45] | High childhood BMI | High body weight in childhood seems to increase the risk of asthma later in life. However, in adults, results are not conclusive. | Yes | 7 |
| Doust et al. [46] | Pesticide exposure | The results were suggestive of potentially adverse associations between pesticide exposure and an increased likelihood of asthma. | Mixed | 7 |
| Jaakkola et al. [47] | Exposure to phthalates | Heated PVC fumes possibly contribute to development of asthma in adults. | Unclear | 6 |
| Folletti et al. [48] | Cleaning work/products | Increased risk of asthma has been shown when exposed to cleaning products. | Unclear | 6 |
| Vincent et al. [49] | Cleaning products | The evidence linking exposure to cleaning agents as a risk factor for causing new onset asthma is limited. | No | 6 |
#Adult-onset asthma indicates whether the study specifies if the target group had adult-onset asthma or whether it is asthma in adults. BMI: body mass index; PVC: polyvinyl chloride.