Addition of Supplementary Foods and Infant Growth (2 to 24 Months)

Objective: To determine the effect of adding supplementary foods on infant growth 2 to 8 and 12 to 24 months.

Methods: Length (cm/month) and weight (kg/month) of white infants (n = 94) were measured five to nine times from 2 to 24 months of age. Mothers reported birth weights, infants’ ages at first introduction of supplementary food, illnesses and information sources about infant feeding. Simple linear regression equations were used to compute slopes for each child (unit changes in length and in weight by age). Stepwise linear regression was used to determine the effect on weight and length slopes by the introduction of supplementary foods (e.g., an infant’s age when cereal, fruit, juice, vegetables and a meat cluster were first added) to the diet. Breast feeding (months duration or ever fed), illness scores and gender were covariates in the regression models.

Results: A significant model (F = 10.09, p = .002) for weight gain (2 to 8 months) showed that gender explained 10% of the variance; for length slope, the model was non-significant and gender explained 3% of the variance. Females had a slower weight gain compared to that of males. None of the covariates or supplementary foods were retained in the models. Weight prior to 12 months was the best predictor (p = .0001, 54% of the variance) of weight gain 12 to 24 months.

Conclusions: Unit changes in weight or length for an infant’s age were not statistically associated with the timing of when supplementary foods were first added to the diet 2 to 8 or 12 to 24 months. Weight prior to 12 months was a significant predictor of weight gain 12 to 24 months.     

Weight gain rate in early childhood and overweight in children 5-11 years old in Salvador, Bahia State, Brazil

Overweight children are more prone to become overweight or obese adults. The most effective prevention is intervention in early childhood. We analyzed the association between early weight gain and overweight/obesity in 1,056 children under 11 years of age. Data were collected on lifestyle, sanitation, socioeconomic status, birth weight, and breastfeeding. Weight gain from birth until different age brackets (< 12, > 12 to 18, > 18 to 24, and > 24 to 60 months) was considered a continuous variable in z-scores. Overweight was defined as body mass index (BMI) > +1 z-score, based on 2006 and 2007 World Health Organization (WHO) guidelines. Poisson regression and linear regression were used in the multivariate statistical analysis. Weight gain rate was associated with BMI, and overweight or obesity in the 5-11-year age bracket increased twofold for each unit increase in the weight gain standard deviation between 24 and 60 months of age (RR = 2.08; 95%CI: 1.87-2.32). For all early childhood age brackets, there was an association between rapid weight gain and subsequent overweight or obesity.     

Physical growth of breast-fed and formula-fed infants from birth to age two years

Weight and length data were collected from birth to age two years on the growth of 159 infants breast-fed for 2–15 months and 150 formula-fed infants. Breast-fed male infants were significantly lighter than formula-fed infants at 6 and 12 months of age (p=0.03 and p=0.009 respectively), but at 24 months the differences were not significant. Breast-fed white females weighed less at 24 mo than their formula-fed counterparts. Using two weight to length indices, statistically significantly fewer infants who were breast-fed for longer periods were categorized as overweight. Incremental weight, weight gain per unit time, was statistically significant only for white males at 6 and 12 months of age. The data suggest that longer breast feeding affects weight and not length.     

Nutritional transition during infancy in East Java, Indonesia: 2. A longitudinal study of growth in relation to the intake of breast milk and additional foods

Weight and length of infants, born in two villages in Madura, East Java were measured longitudinally from birth to 12 months (n = 391). In a sub-sample (n = 76) the intake of breast milk and additional foods during 48 h were also measured. The shape of the weight curve of Madurese infants is comparable to that of healthy, exclusively breast-fed infants in the UK and US during the first 6 months of life, in spite of the custom to force-feed from as early as the first week. The use of a more 'appropriate' growth curve of exclusively breast-fed, healthy infants instead of the NCHS reference failed to define more accurately the age at which growth faltering starts. It is recommended to use weight increments as an indicator of the onset of growth faltering. Breast milk intake correlated significantly with attained weight. However, it explains only a small percentage of the variation in weight, viz. 12-24 per cent. There was no correlation between energy or protein intake from breast milk and additional foods and weight gain.     

Associations between Infant Feeding Practice Prior to Six Months and Body Mass Index at Six Years of Age

Rapid growth during infancy is associated with increased risk of overweight and obesity and differences in weight gain are at least partly explained by means of infant feeding. The aim was to assess the associations between infant feeding practice in early infancy and body mass index (BMI) at 6 years of age. Icelandic infants (n = 154) were prospectively followed from birth to 12 months and again at age 6 years. Birth weight and length were gathered from maternity wards, and healthcare centers provided the measurements made during infancy up to 18 months of age. Information on breastfeeding practices was documented 0–12 months and a 24-h dietary record was collected at 5 months. Changes in infant weight gain were calculated from birth to 18 months. Linear regression analyses were performed to examine associations between infant feeding practice at 5 months and body mass index (BMI) at 6 years. Infants who were formula-fed at 5 months of age grew faster, particularly between 2 and 6 months, compared to exclusively breastfed infants. At age 6 years, BMI was on average 1.1 kg/m² (95% CI 0.2, 2.0) higher among infants who were formula fed and also receiving solid foods at 5 months of age compared to those exclusively breastfed. In a high-income country such as Iceland, early introduction of solid foods seems to further increase the risk of high childhood BMI among formula fed infants compared with exclusively breastfed infants, although further studies with greater power are needed.     

Nutritional status and linear growth of Indonesian infants in west java are determined more by prenatal environment than by postnatal factors

One of the health problems in Indonesia is the high prevalence of stunting in infants. Determinants and specifically the relative contribution of prenatal and postnatal factors to growth and nutritional status of Indonesian infants were investigated. Newborn infants, from women recruited at approximately 18 wk of pregnancy from 9 rural villages in West Java, Indonesia, were followed until 12-15 mo of age. Weight, length, morbidity, breast-feeding and food intake were assessed monthly. Determinants of length and weight increase and nutritional status reflected by Z-scores were evaluated using multiple linear regression. Neonatal weight (3.2 +/- 0.5 kg) and length (49.7 +/- 2.2 cm) were reasonable. However, growth started to falter at 6-7 mo of age, resulting in prevalences of 24% stunting and 32% underweight at 12 mo of age. The multiple regression models explained 19-41% of the variation in growth and nutritional status of infants. Neonatal weight (beta = 0.285) and length (beta = 0.492) were the strongest positive predictors of weight-for-age and height-for-age Z-scores, respectively. Fever was negatively associated with weight increase (beta = -0.144) and weight-for-age (beta = -0.142) and weight-for-height Z-scores (beta = -0.255) but not with length increase or height-for-age Z-scores. Intake of complementary foods was positively associated with increases in weight (beta = 0.190) and length (beta = 0.179) and nutritional status of infants (beta = 0.136-0.194). In conclusion, in this rural population in West Java, neonatal weight and especially length, reflecting the prenatal environment, are the most important predictors of infant nutritional status.     

低出生体重早产儿0～2岁追赶生长的纵向随访研究

目的 分析低出生体重早产儿生后2年内的生长模式及特点,以促进早产儿适宜的体格生长。方法 2012年1月-2015年12月选取青岛大学附属医院儿童保健科规律随访和管理的低出生体重早产儿123例,分为小于胎龄(SGA)儿和适于胎龄(AGA)儿,定期测量体重、身长、头围等数据,采用WHO Anthro软件,计算生后3、6、12、24月龄的体重、身长和头围Z 评分。采用重复测量资料方差分析比较不同特征早产儿生长指标情况。结果 1)早产儿总体体重、身长及头围在生后12个月内Z评分呈上升趋势,但在12~24月龄间Z评分上升不明显。2)SGA与AGA比较,组内效应分析显示:两组体重、身长、头围Z评分总体表现为上升趋势,增长速度以6月龄之前最快,后增速放缓,SGA组身长Z评分在12月龄后转为下降趋势。组间效应显示:在3~24月龄期间,SGA组生后各年龄组体重、身长及头围Z评分值均小于AGA组,差异有统计学意义(F=5.653、5.644、 7.163,P＜0.05)。AGA组在12、24月龄时体重、身长、头围接的评分接近于WHO标准同龄儿童的均值水平。结论 低出生体重早产儿在生后24个月内体重、身长和头围均有追赶生长,追赶生长主要发生在生后12个月内,呈先快后慢的模式,SGA 早产儿各月龄体格生长情况均低于AGA 早产儿。     

Seasonality of growth in Shanghai infants (n=4128) born in 11 consecutive years

OBJECTIVE: To describe the seasonal growth patterns in Shanghai infants, to explore seasonal time lag between weight gain and length gain, and to investigate the long-term effect of birth season on early postnatal growth. DESIGN: Community-based longitudinal study. SETTING: Shanghai, People's Republic of China. METHOD: Children were followed up monthly from 1 to 6 months, 3 monthly from 6 to 12 months, and 6 monthly from 12 to 24 months. SUBJECTS: A total of 6018 children born between 1 January 1980 and 31 December 1990. MAIN OUTCOME MEASURES: Weight gain, length gain and change in body mass index (BMI) over the seasons of the year. RESULTS: The infants tended to grow faster in height in spring and summer, and faster in weight and BMI in autumn and winter. The seasonal effect on weight gain and length gain is largely independent. The mean length value at 1 month of age was about 2.0 cm higher in infants born in May to July than in those born in November to February. At 24 months of age this difference was reduced to about 0.7 cm. CONCLUSIONS: There is a clear and consistent seasonality in growth in Shanghai infants. The seasonality seems to act independently on weight and length. Birth month has some association with attained size, but this is reduced during the first 2 y of life.     

婴儿期增重与5岁以下儿童单纯性肥胖的相关性研究

目的探讨婴儿期增重与5岁以下儿童单纯性肥胖的相关性。方法选取2006年至2011年在中山市博爱医院出生的6746例婴儿进行随访登记,统计相关数据,从中筛选出单纯性肥胖的567例儿童设为肥胖组,并按年龄、性别匹配原则1：1配对者设为对照组,进行父母文化程度、婴儿出生体重、喂养等方面的单因素分析,并进行影响儿童单纯性肥胖的多因素logistics回归分析。结果多因素logistics回归分析显示：与儿童单纯性肥胖显著相关的变量为婴儿出生时的体重（OR=1．94,95％CI=1．56,2．32）、婴儿期前6个月平均增重量（OR=2．17,95％CI=2．11,2．36）及婴儿期后6个月的平均增重量（OR=1．90,95％CI=1．61,2．19）,均P〈0．05。结论与儿童单纯性肥胖密切相关的影响因素为：婴儿出生时的体重、婴儿期前6个月及添加辅食后6个月的平均增重量。     

Effect of timing of introduction of complementary foods on iron and zinc status of formula fed infants at 12, 24, and 36 months of age

OBJECTIVE: The timing of introduction of complementary food to an infant's diet is variable throughout the world. Our objective was to determine whether early introduction of complementary foods affects iron and zinc status of formulated infants at 12, 24, and 36 months of age. DESIGN: A randomized, prospective trial was conducted. Infants were randomly assigned to receive either a) early introduction (at 3 to 4 months of age) of commercially prepared or parent's choice of complementary foods; or b) late introduction (at 6 months of age) of commercially prepared complementary foods or parent's choice of complementary foods. In addition to complementary foods, infants were fed commercial infant formula as recommended by their pediatrician. Hemoglobin, mean corpuscular volume, and serum ferritin and zinc concentrations were determined at 12, 24, and 36 months of age. Three-day diet diaries were completed at 3, 6, 12, 18, 24, 30, and 36 months of age. SUBJECTS/SETTING: One hundred seventy-five infants younger than 3 months were recruited by mailings to parents in the Cincinnati area. Of these, 172 were enrolled, 90 in the early-introduction group and 82 in the late-introduction group. One hundred thirty-three infants (n = 67 in the early, n = 66 in the late group) completed the study. STATISTICAL ANALYSES PERFORMED: Student t test and regression analyses were used to determine whether there were group differences and whether there was a relationship between serum parameters and dietary intake. RESULTS: Infants fed complementary foods early had significantly greater iron intakes until 6 months of age; however, there were no differences in the iron status parameters (ferritin, hemoglobin, and mean corpuscular volume) at 12, 24, or 36 months of age. The early introduction group consumed slightly less zinc than the late introduction group at 5 months (4.4 vs 4.8 mg/day, P < .01) and 6 months (4.4 vs 4.7 mg/day, P < .01). At all other times there were no differences between the early and late group in zinc intakes. The serum zinc concentration was not associated with dietary zinc. Both groups had normal serum zinc concentrations at 12, 24, and 36 months and there were no differences between groups. APPLICATIONS/CONCLUSIONS: The iron and zinc status of infants in this study was not influenced by the timing or type of complementary foods introduced. However, the infants were formula fed and the mean iron and zinc intakes that were equal or greater than the Recommended Dietary Allowances for the first 6 months of age.     

Growth and diet quality are associated with the attainment of walking in rural Guatemalan infants

The attainment of gross motor milestones is an important indicator of motor development in early life; however, little is known about factors affecting gross motor development in children from developing countries. The purpose of this study was to examine the relation of nutritional factors (physical growth and dietary intake) and morbidity during the first year of life to the age of walking without support. Multivariate regression models were used to analyze data collected prospectively between 1991 and 1999 in rural Guatemala. Attainment of children's gross motor milestones was assessed monthly by trained field workers using the 17-milestone Gross Motor Development Scale, morbidity was assessed by biweekly recall, and dietary intakes were measured at 9 and 12 mo of age using repeated 24-h dietary recalls. Median age of walking was 15 mo (range 10-24 mo; n = 174) with no differences by gender. Models were adjusted for birth order, gender, gestational age, maternal age and education, socioeconomic status, and community. Growth in length (-0.57 +/- 0.27 mo length for age Z-score; P = 0.04) and weight (-0.54 +/- 0.19 mo weight for age Z-score, P = 0.005) during the first year of life, rather than size at birth, predicted age of walking. Animal protein intake from complementary foods, while low (mean < 1 g/d) overall, was positively associated with earlier age of walking (P = 0.02). Morbidity during infancy was not associated with age of walking. These findings indicate the importance of prevention of postnatal growth retardation and improvement of diet quality for children's gross motor development.     

An energy-dense complementary food is associated with a modest increase in weight gain when compared with a fortified porridge in Malawian children aged 6-18 months

Poor complementary feeding practices are associated with stunting and growth faltering throughout the developing world. The objective was to compare the effect of using peanut-/soy-based fortified spread (FS) and corn porridge fortified with fish powder (FP) as complementary foods on growth in rural Malawian children. A total of 240 children were enrolled at the age of 6 mo and randomized to receive FS or FP. Both complementary foods provided 836 kJ/d from 6 to 9 mo of age and 1254 kJ/d from 9 to 18 mo of age. Children were followed monthly for anthropometry and fortnightly for the symptoms of fever, cough, or diarrhea until they were 18 mo old. Zn and Se status were assessed at 6 and 12 mo. The primary outcomes were the rates of weight and length gain from 6-12 mo and from 12-18 mo. Children who received FS gained 110 g more (95% CI 220 to 10) from 6-12 mo of age than children receiving FP. Weight gain did not differ between children receiving FS and FP between 12 and 18 mo of age, nor did statural growth from 6 to 12 mo or 12 to 18 mo. A total of 23% of all children were Zn deficient at 6 mo of age and this increased to 37% at 12 mo of age. Neither FS nor FP was associated with significantly improved Zn status. FS was associated with better weight gain from 6-12 mo of age and may be useful in conjunction with additional interventions to improve infant growth in the developing world.     

Determinants of pregnancy outcome and newborn behavior of a semirural Egyptian population

Several potential determinants of birth weight and neonatal behavioral organization, ie, maternal anthropometry, food intake (energy, protein, and plant- and animal-source foods), morbidity, and household socioeconomic status, were followed systematically in a semirural Egyptian population during greater than or equal to 6 mo of pregnancy. In early pregnancy mothers were generally normal weight to moderately overweight. Their mean energy intake, largely from plant sources, was approximately 8.37 MJ/d (2000 kcal/d) during trimesters 2 and 3. Early (3 mo) pregnancy weight and weight gain during trimesters 2 and 3 were significantly positively related to birth weight Z scores. The best predictor model examined for birth weight included early pregnancy weight, weight gain, and length of gestation (R2 = 0.45). Early pregnancy weight and maternal intake of animal-source foods were significant positive predictors of the newborn's orientation and habituation behavior, respectively. Habituation and orientation measures assess the infant's early ability to process information.     

Food groups as predictors for short-term weight changes in men and women of the EPIC-Potsdam cohort

This study examined the effect of food group intake on subsequent 2-y weight change. Food-frequency questionnaire-based food intake data of 17,369 nonsmoking subjects of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort were examined in their relation to a subsequent weight change. Dietary data, collected from 1994 to 1998, were grouped into 24 food groups. Weight change per year follow-up was the outcome of interest; large weight gain was defined as > or =2 kg; small weight gain as > or =1 kg to <2 kg; large weight loss as < or = -2 kg; small weight loss as < or = -1 kg to > -2 kg and weight maintenance as +/- 1 kg. For each food group, a separate polytomous logistic regression model with stable weight as the reference group was constructed, controlling for age, body mass index, previous weight change, and behavioral and lifestyle factors. Odds ratios (OR) and 95% confidence intervals (CI) estimated the increase in risk associated with each 100 g/d increment in food group intake. In women, consumption of high energy, high fat food groups significantly predicted large weight gain, e.g., fats (OR = 1.75; 95% CI, 1.01-3.06), sauces (OR = 2.12; 95% CI, 1.17-3.82) and meat (OR = 1.36; 95% CI, 1.04-1.79), and the consumption of cereals predicted large weight loss (OR = 1.43; 95% CI, 1.09-1.88). In men, intake of high energy, high sugar foods, i.e., sweets, was significantly predictive of large weight gain (OR = 1.48; 95% CI, 1.03-2.13). Our data show that a diet rich in high fat and high energy foods predicts short-term weight gain even if controlled for many potential confounding factors.     

Breast and complementary feeding practices in relation to morbidity and growth in Malawian infants

OBJECTIVES: The objective of this study was to compare growth, morbidity incidence and risk factors for undernutrition between infants receiving complementary feeding early, before 3 months of age, with those receiving complementary foods after 3 months in a poor rural Malawian community. METHODS: A cohort of babies was enrolled at birth for follow-up to 12 months of age. Weight, length, morbidity and feeding patterns were recorded at 4 weekly intervals from birth to 52 weeks. RESULTS: Mean age at introduction of water was 2.5 months (range 0-11.8), complementary foods 3.4 months (range, 1.0-10.7) and solids 4.5 months (range 1.2-13.8). Over 40% of infants had received complementary foods by 2 months and 65% by 3 months. The proportion of exclusively breast-fed infants, which included those receiving supplemental water, was 13% at 4 months, 6.3% at 5 months and 1.5% at 6 months. Infants with early complementary feeding had lower weight for age at 3 and 6 months (P<0.05), and at 9 months (P=0.07) and at 2 months they were approximately 200 g lighter. Early complementary feeding was significantly associated with increased risk for respiratory infection (P<0.05), and marginally increased risk for eye infection and episodes of malaria. Maternal illiteracy was associated with early complementary feeding (OR=2.1, 95% CI 1.3, 3.2), while later complementary feeding was associated with reduced infant morbidity and improved growth. CONCLUSION: Breast-feeding promotion programmes should target illiterate women. Greater emphasis is required to improve complementary feeding practices.     

Relation between changes in intakes of dietary fiber and grain products and changes in weight and development of obesity among middle-aged women

BACKGROUND: Although increased consumption of dietary fiber and grain products is widely recommended to maintain healthy body weight, little is known about the relation of whole grains to body weight and long-term weight changes. OBJECTIVE: We examined the associations between the intakes of dietary fiber and whole- or refined-grain products and weight gain over time. DESIGN: In a prospective cohort study, 74,091 US female nurses, aged 38-63 y in 1984 and free of known cardiovascular disease, cancer, and diabetes at baseline, were followed from 1984 to 1996; their dietary habits were assessed in 1984, 1986, 1990, and 1994 with validated food-frequency questionnaires. Using multiple models to adjust for covariates, we calculated average weight, body mass index (BMI; in kg/m(2)), long-term weight changes, and the odds ratio of developing obesity (BMI > or = 30) according to change in dietary intake. RESULTS: Women who consumed more whole grains consistently weighed less than did women who consumed less whole grains (P for trend < 0.0001). Over 12 y, those with the greatest increase in intake of dietary fiber gained an average of 1.52 kg less than did those with the smallest increase in intake of dietary fiber (P for trend < 0.0001) independent of body weight at baseline, age, and changes in covariate status. Women in the highest quintile of dietary fiber intake had a 49% lower risk of major weight gain than did women in the highest quintile (OR = 0.51; 95% CI: 0.39, 0.67; P < 0.0001 for trend). CONCLUSION: Weight gain was inversely associated with the intake of high-fiber, whole-grain foods but positively related to the intake of refined-grain foods, which indicated the importance of distinguishing whole-grain products from refined-grain products to aid in weight control.     

Increased gain in bone mineral content of preterm infants fed an isocaloric, protein-, and mineral-enriched postdischarge formula

Purpose

Preterm infants are at risk for suboptimal bone mineralization. Postnatal bone formation requires optimal nutritional composition. This study evaluated the effect of isocaloric, protein-, and mineral-enriched postdischarge formula (PDF), standard term formula (TF), and human milk (HM) on gain in bone mineral content (BMC) of preterm infants between term age (40 weeks postmenstrual age) and 6 months corrected age (CA).

Methods

Between term age and 6 months CA, 93 preterm infants were randomized to be fed PDF (n = 52) or TF (n = 41) and 46 preterm infants were fed HM. Weight (g) and length (cm) were measured at birth, term age, and 6 months CA. BMC (g) was measured by whole-body dual-energy x-ray absorptiometry at term age and 6 months CA.

Results

Gain in BMC (expressed as median with interquartile range) between term age and 6 months CA was higher in PDF-fed infants (102.3 (32.4) g) compared to TF- and HM-fed infants (91.6 (24.5) and 84.5 (33.3) g, respectively), adjusted for gender, gestational age, birthweight, and gain in weight and length.

Conclusion

Between term age and 6 months CA, isocaloric PDF enhances gain in BMC of preterm infants, independent of gain in weight and length. We speculate that higher gain in BMC during infancy may improve adult bone mass in preterm infants.     

广州市社区足月小样儿 0~2岁体格发育的纵向研究

目的 了解足月小样儿生后2年内的体格发育和营养状况,为制定足月小样儿生长发育干预策略提供科学依据。方法 采用前瞻性的研究方法,选取2016年1月—2018年4月广州出生的足月小样儿为小于胎龄儿(SGA)组,选取同种族、同社区、同年龄的足月正常体重儿为适于胎龄儿(AGA)组,定期对生长参数进行了纵向评估,比较两组儿童体格发育特点。结果 1) SGA组生后各年龄组体重和身长Z评分均小于AGA组,但生后第一年Z评分呈上升趋势,体重增长(△Z评分为1.17±1.10)、身长增长(△Z评分为0.65±1.23)均大于AGA组。2) 67.65%和50.98% 的SGA在婴儿期出现体重和身长追赶生长;婴儿期生长速率与2岁时营养状况相关(P<0.01)。3) SGA组在各年龄的低体重、生长迟缓、消瘦率均高于AGA组,2岁时发生率在8%~15%。超重和肥胖率低于AGA组,2岁时超重率为2.94%。两组间低体重、生长迟缓和超重率比较,差异有统计学意义(χ²=4.40、4.18、5.38,P<0.05); SGA组6月龄贫血患病率高达43.63%。结论 足月小样儿生后一年内体重和身长均有追赶生长。营养不良发生状况不容忽视,应注意预防足月小样儿营养不良和6月龄贫血。     

辅食添加对婴幼儿贫血的影响

【目的】 本研究以健康婴幼儿为研究对象,研究不同时间添加辅食、添加不同种类辅食对婴幼儿贫血发生的影响。 【方法】 采用整群抽样的方法,选择北京顺义区3~18月龄婴幼儿143名,向其母亲询问婴儿基本状况、添加辅食时间和辅食种类等;采用氰化高铁血红蛋白方法测量其血红蛋白浓度。 【结果】 本研究发现该组儿童贫血发生率12个月前为30%左右,明显高于12个月后的10%左右 (P< 0.01)。不论男童还是女童, 6个月龄前或6个月龄后儿童,4个月前添加辅食均可以使贫血发生率下降(P< 0.05)。添加铁强化食物(如配方奶和营养素补充剂)可以使血红蛋白浓度升高(P< 0.05)。采用不同贫血诊断标准(97、105、110 g/L),贫血发生率差异仍存在统计学意义 (P< 0.01)。 【结论】 12个月龄前儿童贫血发生率明显高于12个月龄后儿童。虽然4个月前添加铁强化辅食使得铁营养状况得到改善,但适宜的辅食添加时间有待进一步研究。