title: Effects of smoking, mother's age, body mass index, and parity number on lipid, protein, and secretory immunoglobulin A concentrations of human milk.
abstract: OBJECTIVE
  This study investigated the effect of smoking, mother's age, body mass index (BMI), and parity number on density, lipids, proteins, and secreted immunoglobulin A (SIgA) of human milk.
  
  
  METHODS
  Transitional and mature milk samples were collected from 23 nursing smoker mothers and 43 nursing nonsmoker mothers. Proteins, lipids, and SIgA concentrations were determined as well as the milk density and the general protein profile.
  
  
  RESULTS
  Our investigation showed that the milk of smokers contained less lipids and proteins (statistically significant 26% and 12% decrease, respectively), whereas milk density was unchanged. SIgA concentration was 27% lower in milk from smokers, but the decrease was not statistically significant. The general protein profile showed no significant smoking-associated changes in the four identified proteins (β-casein, immunoglobulin A heavy chain, serum albumin, and lactoferrin). Mothers' age and residential area showed noticeable but statistically nonsignificant differences in some of the measured parameters. However, parity number, lactation stage, and BMI were associated with a significant modification of milk composition. Mature milk contained more lipids and less protein, whereas the increase of parity number was associated with an increase in lipid concentration. The group of overweight mothers showed lower milk protein concentration in comparison with the normal group. Multivariate analysis showed a statistically significant interaction effect of the variables (smoking, parity number, lactation stage, age, and BMI) on lipids and between some of them on proteins and SIgA.
  
  
  CONCLUSIONS
  Our study showed that smoking was associated with lower milk lipid and protein concentrations and that the parity number and BMI were associated with a change in milk lipids and proteins content, respectively.
authors.affiliation: Faculty of Sciences I, Lebanese University, Beirut, Lebanon.
authors.forename: Pamela
authors.initials: P
authors.lastname: Bachour
authors.forename: Rula
authors.initials: R
authors.lastname: Yafawi
authors.forename: Farouk
authors.initials: F
authors.lastname: Jaber
authors.forename: Elias
authors.initials: E
authors.lastname: Choueiri
authors.forename: Ziad
authors.initials: Z
authors.lastname: Abdel-Razzak
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001942:Breast Feeding; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000378:metabolism*; D007231:Infant, Newborn; D007774:Lactation / Q000502:physiology; D008055:Lipids; D008423:Maternal Age; D008894:Milk Proteins / Q000378:metabolism; D008895:Milk, Human / Q000737:chemistry / Q000378:metabolism*; D009753:Nutritive Value; D010298:Parity; D011247:Pregnancy; D012907:Smoking / Q000009:adverse effects / Q000378:metabolism*; D055815:Young Adult
chemical_list: D007071:Immunoglobulin A, Secretory; D008055:Lipids; D008894:Milk Proteins