Oktawia (Octavia) Borecka

Title: Age-related ability to synthesise Vitamin D in the skin on exposure to sunlight.

PhD summary

Vitamin D supports a number of important physiological functions and is well recognized for its role in musculoskeletal health. It’s production in skin commences on exposure to ultraviolet B radiation of its precursor 7-dehydrocholesterol. It has been hypothesised that the body’s vitamin D status is lower in the older-aged due to lower concentrations of 7DHC in their skin. However, apart from one study (MacLaughlin and Holick, 1985) this has not been further investigated, yet the original research has been questioned due to inconsistencies in methodology. Therefore, it is not certain what puts the older-aged at risk of lower vitamin D status. It could be due to decreased 7DHC levels in skin, but also to changes in lifestyle and activity with advancing years. As people age, they are perceived to spend less time outdoors, and expose less unprotected skin hence receiving less UV radiation. However, this may no longer be true for all, as healthy-life expectancy continues to increase. 

In my PhD project I will aim to identify whether vitamin D production in the skin of elderly people is 7DHC limited or UVB limited to find out why the elderly tend to have lower vitamin D levels. I will be carrying out a clinical study which involves taking blood and skin samples from two cohorts of healthy adult volunteers (‘young’ and ‘elderly’) prior and post UV exposure in solar simulated radiation cabinets.

The aim is to identify whether vitamin D production in the skin of elderly people is 7DHC limited or UVB limited.

Once the skin and blood samples have been collected they will be analysed for vitamin D metabolites from the precursor 7DHC through to 25(OH)D, the circulating form that is used as a measure of vitamin D status. Development of the assay for 7DHC quantification in skin by High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) is also a key objective of this project. The results of this study will help answer the question of why the elderly are at risk of lower vitamin D status, and improve medical guidance in that area.


September 2017 – September 2021



Institution name

The University of Manchester


  • Prof Ann Webb
  • Prof Lesley Rhodes
  • Prof William Fraser (external; University of East Anglia) 

Discipline area

Skin photobiology

Short biography 

  • Master of Science, University College London (UCL), 2014
  • Bachelor of Science, The University of Manchester, 2013  

Contact details

Email: oktawia.borecka@postgrad.manchester.ac.uk