Related by context. Frequent words. (Click for all words.) 52 swimming 50 asthmatics 48 ultraviolet UV radiation 47 swim 47 wear sunscreen 46 Passive smoking 46 indoor allergens 46 cryptosporidiosis 46 aggravate asthma 45 asthma 45 asthma bronchitis 45 swum 45 chlorinated 45 asthma sufferers 45 Aerobic exercise 45 inhaled steroids 45 asthma allergies 45 animal dander 45 asthma triggers 44 swimming pools 44 atopy 44 Thomas Lurz 44 atopic 44 harmful ultraviolet rays 43 diarrheal illness 43 UV exposure 43 cotinine levels 43 bathers 43 asthma exacerbations 43 asthmatic 42 sunbathe 42 vitamin D deficiency 42 solariums 42 sunbathing 42 swimmers 42 Asthmatics 42 pools spas 42 coughing wheezing 42 sunburns 42 vitamin D deficient 42 airborne allergens 42 aqua aerobics 42 allergies asthma 42 methyl mercury 42 Applied Physiology 41 containing DEET 41 Swimming pools 41 cardio vascular disease 41 bathing 41 sunburn 41 silica dust 41 airflow obstruction 41 skin irritations 41 Tanning beds 41 sun ultraviolet rays 41 tanning booths 41 venous thrombosis 41 infrared sauna 40 secondhand smoke exposure 40 Prolonged exposure 40 fluid intake 40 insect repellent containing DEET 40 vitamin D insufficiency 40 ultraviolet UV light 40 polycyclic aromatic hydrocarbons PAHs 40 UV radiation 40 bronchiolitis 40 elevated triglycerides 40 upper respiratory tract 40 pools 40 swims 40 UV rays 40 suncream 40 mechanical ventilation 40 swimming pool 40 recurrent infections 40 pool 40 asthma emphysema 40 vitamin D intake 40 building sandcastles 40 dust mite 40 RSV infection 40 eczema 40 postmenopausal breast cancer 40 Epidemiological studies 40 Vitamin D deficiency 40 rhinitis 40 aerobic activity 40 rotavirus gastroenteritis 39 carcinogenic substances 39 occupational exposures 39 passive smoking 39 strenuous exercise 39 induced asthma 39 ultraviolet radiation 39 physical exertion 39 Asthmatic 39 sunscreen 39 Swimming 39 colds 39 snorkellers