Ma et al. BMC Public Health 2012, 12:568 http://www.biomedcentral.com/1471-2458/12/568 Table 1 Variables and scoring system used to construct the infant and child feeding index (CS-ICFI) Variables Breastfeeding Food consistency a Feeding frequency (past 24-h) b Food group frequency score (FGFS) (past 7-d) Dietary diversity score(DDS) (past 7-d) Total score scores Visit 1 (6-month-old) Yes = +2 No = 0 Liquid = 0 Gruel-like = +1 Semi-solid = +2 No = 0 1 times = +1 ≧2 times = +2 FGFS 0 ~ 3 = 0 FGFS 4 ~ 9 = +1 FGFS 10 ~ 16 = +2 DDS 0 ~ 2 = 0 DDS 3 ~ 4 = +1 DDS 5 ~ 8 = +2 10 points Visit 2 (12-month-old) Yes = +1 No = 0 Gruel-like = 0 Semi-solid = +1 Solid = +2 0-2 times =0 3-4 times or ≧9 times = +1 5-8 times = +2 FGFS 0 ~ 5 = 0 FGFS 6 ~ 9 = +1 FGFS 10 ~ 12 = +2 FGFS 13 ~ 16 = +3 DDS 0 ~ 3 = 0 DDS 4 ~ 6 = +1 DDS 7 ~ 8 = +2 10 points Page 3 of 9 Visit 3 (18-month-old) Yes = 0 No = 0 Gruel-like = 0 Semi-solid = +1 Solid = +2 0-2 times =0 3-4 times = +1 ≧9 times = +2 5-8 times = +3 FGFS 0 ~ 7 = 0 FGFS 8 ~ 11 = +1 FGFS 12 ~ 14 = +2 FGFS 15 ~ 16 = +3 DDS 0 ~ 4 = 0 DDS 5 ~ 7 = +1 DDS 8 = +2 10 points aFood consistency was the highest consistency of complementary food. bFor Visit 1, feeding frequency of breastfeeding and formula-feeding was excluded; for Visits 2 and 3, the times of taking all food groups consumed above 10 g were counted. Breastfeeding A score of +2, +1 was given to 6-, 12-month-old infants who were breastfed respectively. Among young children aged 18 months, only 3 were breastfed, and for elder child, complementary feeding is considered more im- portant than breastfeeding, so a score of 0 was given to 18-month-old young children who were breastfed. A score of 0 was given to non-breastfeeding infants at all ages. Food consistency Food consistency was used as a component of CS-ICFI instead of bottle feeding because bottle use is considered potentially harmful for all children throughout the age range included. Food consistency was defined as the highest consistency of complementary food. For 6- month-old infants, liquid food was given a score of 0, gruel-like food +1, and semi-solid food +2. For 12- and 18-month-old infants, gruel-like food, semi-solid food, and solid food were scored as 0, +1, and +2, respectively. Feeding frequency Feeding frequency means how many times the infants was offered different foods in the previous 24 h. For 6- month-old infants, feeding frequency was used to ac- count the times for complementary foods excluding breastfeeding and formula-feeding. None (meaning no complementary foods) was given a score of 0, 1 time a day received a score of +1 and 2 times or more +2. For 12- and 18-month-old infants, the times of taking all food groups consumed above 10 g were counted as shown in Table 1. Dietary diversity score (DDS) DDS was calculated on the basis of the number of differ- ent food groups infants consumed over the past 7 days. Eight food groups were taken into account which included the major nutritionally important types of food the infants may have eaten in our context, as follows: 1) starchy staples (foods made from grain, roots, or tubers); 2) legumes and nuts; 3) dairy (milk other than breast milk, cheese, or yogurt); 4) meat, poultry, or liver/organ meats 5) fish, shrimp or crabs; 6) eggs; 7) fruits and 8) vegetables. Each food group consumed by infants during the previous week was scored as 1. These scores were summed to give a possible range of 0-8, and then new scores were assigned as described in Table 1 according to different age distribution. Food group frequency score (FGFS) FGFS was assessed based on the frequency of different food groups consumed by infants over the past 7 days. FGFS was scored as 0 if not consumed during the previ- ous week, +1 if consumed on 1-3 days, and +2 if