Thank you for suggesting that we reference these two papers, Darmon and Drewnoski was very insightful and most certainly useful for this article, and we now make it clearer that education is a factor of SES and a proxy for income. Lines 419-428 offer an insight into income and affluence, however we have elaborated more on income in future perspectives 533-537 and in the conclusion, lines 550-555 as it may, as you say, play a significant role in these associations.
To assist the reader’s comprehension, explain the instruments more as you develop the paper.