Age&AMR

Why does AMR vary by age?

During my CDA, I’m trying to understand why prevalence of antibiotic resistance in infection varies by age. I’ve been told so many reasons that I’m trying to keep a list here. If you have any more do get in touch! Many of these reasons have been prompted by Naomi Waterlow and my first analysis of some European infection data, published here. Most of the below reasons are high income setting specific, with a focus on understanding these HIC patterns, but some are general to global settings.

• Antibiotic use varies by age
  • Shape: Mostly in a “U” shape
  • Selection: should be more in younger / older ages
  • Suggests: AMR should peak at younger and older ages
  • Signal / data needs: antibiotic use by age/sex over time
• Contact with healthcare settings varies by age
  • Shape: Similar “U” shape to antibiotic use
  • Transmission: Resistant pathogens circulate more in hospitals
  • Selection: And those in hospitals get more antibiotic use / exposure
  • Suggets: AMR should peak at younger and older ages
  • Signal / data needs: admission / hospital inpatient data
• Immunosenescence
  • Shape: Exponential decline with age, and some variation in childhood
  • Infection burden: Will increase with age
  • Selection: leading to more infections with age => more antibiotic use
  • Transmission: leading to more infections with age => more contact with high transmission healthcare
  • Suggests: AMR should peak at older ages
• Microbiome disruption
  • Selection: over a lifetime, antibiotic exposure effects, which disrupt the microbiome, accumulate
  • Shape: exponential increase with age
  • Suggests: AMR should peak at older ages
• Antibiotic use has increased over time
  • Selection: cohort effect possible, older people were exposed to less antibiotics at younger ages than younger people now
  • Shape: younger people have had more cumulative antibiotic exposure, which is key to AMR colonisation and subsequent infection
  • Suggests: AMR higher at younger ages, with plateau effect increasing with age and time
• Global travel leads to AMR colonisation
  • Transmission: younger people go “travelling” and bring AMR from AMR hotspots to Europe
  • Suggests: AMR prevalence in infection higher in younger ages
  • Signal / data needs: may be only true for those bug-drug combinations that do have AMR hotspots / travel associated data
• Hormonal shifts at menarche and menopause
  • Shape: should see peaks/changes at onset of menarche (teenage) and then menopause (40-50s)
  • Infection burden: microbiome shifts may lead to changes
  • Suggests: should see shifts at key ages in women
  • Signal / data needs: data on impact of these shifts on infection / antibiotic use especially UTIs