Diet, energy expenditure, and body composition of lactating Ribeirinha women in the Brazilian Amazon.

Lactation is the most energetically demanding part of human reproduction; yet, compared with pregnancy, we know little about the strategies women in different settings employ to cope with these increased energy demands. This paper takes a biocultural approach and reports longitudinal data on the anthropometry, dietary intakes and energy expenditure of a sample of 23 rural, lactating Ribeirinha women living in subsistence-based communities in the eastern Amazon. The dietary intakes of these lactating women were insufficient to meet their lactating energy needs and were least sufficient during resguardo, a 40-day period in the immediate postpartum when the women observed a series of food taboos and work restrictions. Instead, the women in this study met the increased energy demands of lactation by drawing on their energy reserves and reducing their energy expenditure in physical activity. The women showed a significant reduction in weight (P<0.001), BMI (P<0.001) and in circumferences (hip, P=0.01; waist, P=0.03) and skinfolds (thigh, P=0.03) in the gluteal femoral region. Total daily energy expenditure (TDEE) was lowest during resguardo and increased as lactation progressed (P=0.01). While the practice of resguardo reduced maternal energy expenditure and allowed women more time to spend with their newborn infants, it came at a cost (low dietary intake), which appears to be related to the loss of the adult woman from subsistence activities. By taking a biocultural approach this study illustrates the role the social environment plays in shaping the experience of lactating women.     

Impact of breastfeeding on anthropometric changes in peri‐urban Toba women (Argentina)

We present an analysis of the effect of lactation on average maternal anthropometric and body composition measures in a population of Toba women in Formosa, Argentina. This indigenous population is undergoing a continuing transition from a seminomadic hunter–gatherer lifestyle to a sedentary, peri‐urban one. Using a mixed‐longitudinal design, we measured monthly maternal body mass index (BMI), body fat percentage, and triceps and subscapular skinfold thickness between birth and the 18th month postpartum in 113 breastfeeding women. The pattern of change in postpartum body composition varied with maternal age. Adult women (20 years old and older) did not show significant changes in any of the anthropometric measures during the entire study. Older adult women (30 years old and older) consistently had the highest values in measures of BMI and percentage fat, and tended to retain weight postpartum. Adolescent subjects (19 years old and younger) tended to lose weight during the first 6 months postpartum but regain their prepregnancy weight by 12 months postpartum. The same patterns were observed for changes in body fat percentage and in skinfold thickness. We conclude that in this population the energetic stress of lactation does not pose a serious challenge to the maintenance of long‐term maternal energy balance or to short‐term energy balance in women over 20 years of age. From a public health perspective, postpartum weight retention in older women may represent a more serious health threat. The low level of energetic stress associated with lactation may also contribute to the relatively short duration of lactational amenorrhea in this population despite a cultural pattern of intensive breastfeeding. Am. J. Hum. Biol. 15:717–724, 2003. © 2003 Wiley‐Liss, Inc.     

Lactation,seasonality, and mother's postpartum weight change in Bangladesh: An analysis of maternal depletion

Longitudinally collected data from rural Bangladesh was used to investigate the effects of lactation, reproductive patterns, and seasonality on maternal weight and postpartum weight change. Results of multivariate analyses demonstrate that weight change exhibits a strong seasonal pattern, with losses in winter (December through March) and the rainy season (July through November) and gains in other months. The rate of weight loss peaks between 5 and 9 months postpartum, declines to near zero by 16 months postpartum, and becomes positive thereafter. However, season and duration interact, so that women who reach the stage of most intensive nutritional demand at a time of low food supply relative to energy output lose considerably more weight than women who reach that stage when food supplies are more adequate. Currently lactating women lose weight more rapidly than nonlactating women. Weight loss is slower among women with low initial weight. Prior reproductive patterns are associated with both weight at the time of conception and weight gain during pregnancy, which together determine weight at the beginning of the lactation interval. Each additional birth is associated with a decrease of 280 g in weight at conception, whereas interpregnancy intervals of < 18 months are associated with an 800-g deficit at the time of that conception compared to longer intervals. Weight gain during pregnancy is greater among women with high parity, short interpregnancy intervals, and lower weight at conception, but not enough to compensate for the prepregnancy deficit. © 1994 Wiley-Liss, Inc.     

Associations between the number of natural teeth in postmenopausal women and duration of lactation: The 2010–2012 Korea National Health and Nutrition Examination Survey

ObjectivesLactation is reported to be associated with changes in maternal calcium homeostasis. The relationship between lactation and long-term oral health remains to be revealed. This study was aimed to evaluate the relationship between lactation and the number of natural teeth in postmenopausal women using nationally representative data.MethodsThe data from the Korea National Health and Nutrition Examination Survey between 2010 and 2012 were used, and the analysis in this study was confined to 4211 respondents over 19 years old who had gone through menopause and had no missing values for the reproductive factors and outcome variables. The total number of natural teeth was then calculated after excluding third molars. Multiple logistic regression analyses were used to assess the associations of the number of natural teeth and lactation.ResultsAs the duration of total lactation increased, the number of natural teeth decreased. Average duration of lactation per child showed similar trends. The association between the total duration of lactation and the number of natural teeth showed an inverse relationship with a beta value of −0.0181 per day after adjustment, and the beta value of the average duration of lactation per child was −0.0287 after the adjustment. The odds ratios of the percentage of individuals with the number of teeth ≤27 tended to increase with increased duration of lactation. Adjusted odds ratios and 95% confidence intervals were 1.830 (1.009, 3.320); 1.142 (0.765, 1.704); 1.159 (0.807, 1.664); and 0.857 (0.563, 1.306) for lactation period of ≥25 months, 13–24 months, 7–12 months, ≤6 months, and no lactation, respectively.ConclusionsThis study investigated the relationship between the number of teeth and the total duration of lactation or an average duration of lactation per child using nationally representative data. Total duration of lactation and average duration of lactation per child were inversely related to the number of natural teeth. Lactation may be considered to be an independent risk indicator for tooth loss in Korean postmenopausal women.     

Resumption of ovarian function during lactational amenorrhoea in breastfeeding women with polycystic ovarian syndrome: metabolic aspects

BACKGROUND: Polycystic ovarian syndrome (PCOS) is a common endocrine-metabolic disorder in women, a high percentage of whom exhibit peripheral insulin resistance. After delivery, in normal women, lactation imposes a metabolic adaptation, the impact of which on the insulin resistance of PCOS patients is not known. The aim of this study was to evaluate the effect of lactation on insulin resistance, glucose and insulin metabolism, and sex hormone-binding globulin (SHBG) and insulin-like growth factor binding protein-1 (IGFBP)-1 concentrations in fully breast-feeding normal and PCOS women during the postpartum period (lactational amenorrhoea) and also after weaning. METHODS: Twelve lactating PCOS (LPCOS) women and six normal lactating (NL) women of similar age and body mass index (BMI) were selected for the study. At the 4th and the 8th week postpartum (pp), and 8 weeks after weaning, a 2 h, 75 g oral glucose tolerance test (oGGT) was performed, followed by an insulin tolerance test 2 days later. For the oGGT, glucose and insulin were measured in each sample and SHBG and IGFBP-1 were determined in the fasting sample. RESULTS: During lactation, fasting insulin levels were similar in both groups. In LPCOS women 2 h insulin concentrations were significantly higher, and SHBG and IGFBP-1 concentrations were significantly lower, than those observed in NL women. In both groups, insulin sensitivity evaluated by the insulin tolerance test was not modified. After weaning, in LPCOS women, SHBG and IGFBP-1 concentrations remained lower and insulin concentrations remained higher than those observed in NL women ( P < 0.05 ). CONCLUSIONS: In PCOS women, insulin resistance is not modified during lactation. Lactation has a transitory beneficial effect on insulin levels and biological markers of insulin resistance.     

The effect of weight loss in overweight, lactating women on the growth of their infants

BACKGROUND: The retention of weight gained during pregnancy may contribute to obesity. Lactation should promote weight loss, but weight loss is highly variable among lactating women. The risks associated with the restriction of energy intake during lactation have not been adequately evaluated. The purpose of this study was to determine whether weight loss by women during lactation affects the growth of their infants. METHODS: We randomly assigned 40 breast-feeding women who were overweight (defined as a body-mass index [the weight in kilograms divided by the square of the height in meters] of 25 to 30) at 4 weeks post partum either to restrict their energy intake by 500 kcal per day and to exercise for 45 minutes per day for 4 days per week (the diet-and-exercise group) or to maintain their usual dietary intake and not exercise more than once per week for 10 weeks (the control group). We measured the weight and fat mass of the women and the weight and length of the infants before, during, and at the end of the study period. RESULTS: The mean (+/-SD) energy intake decreased by 544+/-471 kcal per day in the diet-and-exercise group. As compared with the control group, the women in the diet-and-exercise group lost more weight (4.8+/-1.7 kg vs. 0.8+/-2.3 kg, P<0.001) and fat mass (4.0+/-2.0 kg vs. 0.3+/-1.8 kg, P<0.001). The gains in weight and length of the infants whose mothers were in the diet-and-exercise group (1925+/-500 g and 7.8+/-2.0 cm, respectively) were not significantly different from those of the infants whose mothers were in the control group (1861+/-576 g and 7.3+/-1.7 cm). CONCLUSIONS: Weight loss of approximately 0.5 kg per week between 4 and 14 weeks post partum in overweight women who are exclusively breast-feeding does not affect the growth of their infants.     

The common obesity variant near MC4R gene is associated with higher intakes of total energy and dietary fat, weight change and diabetes risk in women

Melanocortin-4 receptor (MC4R) plays critical roles in regulating food intake and energy balance. Recent genome wide scans found common variants near MC4R were related to obesity and insulin resistance. We examined the associations of the reported variants rs17782313 (T>C) and rs17700633 (G>A) with dietary intakes, weight change and diabetes risk in 5724 women (1533 with type 2 diabetes) from a prospective cohort. Under an additive inheritance model, SNP rs17782313 was significantly associated with high intakes of total energy (P = 0.028), total fat (P = 0.008) and protein (P = 0.003). Adjustment for age, BMI, diabetes status and other covariates did not appreciably change the associations. The SNP was also associated with significantly increasing trend of percentage of energy from total fat (P for trend = 0.037). The associations between SNP rs17782313 and higher BMI (P = 0.002) were independent of dietary intakes. In addition, carriers of allele-C had 0.2 kg/m(2) greater 10-year increase in BMI from cohort baseline 1976 to 1986 (P = 0.028) compared with the non-carriers. Moreover, per allele-C of rs17782313 was associated with 14% (2-32%) increased risk of type 2 diabetes, adjusting for BMI and other covariates. SNP rs1770833 was not significantly associated with either dietary intakes or obesity traits. In conclusion, the common SNP rs17782313 near MC4R gene was significantly associated with higher intakes of total energy and dietary fat. In addition, the SNP was related to greater long-term weight change and increased risk of diabetes in women.     

Pregnancy and lactation in the obese rat: Effects on maternal and pup weights

Lister hooded female rats, fed palatable high energy foods and chow, weighed significantly more than chow-fed control rats before mating. A smaller proportion of the obese rats became pregnant, and they lost more litters in lactation. When litters survived (7±1 pups), maternal weight changes differed between groups during lactation. The controls gained 6.2±3.2 g, whereas the obese rats lost variable amounts of weight despite the continued availability of the palatable diet. The rats that were heaviest at mating and parturition and which showed the largest non-fetal weight gains in pregnancy (i.e., the “large weight loss group”) lost 60.6±4.8 g, while less obese rats which showed similar non-fetal gains to controls (i.e., the “small weight loss group”) lost 24.6±3.2 g. Thus the weights of all groups converged and were similar after three weeks of lactation, but diverged again after weaning. During lactation the total energy intakes and amounts of protein consumed by the obese rats were significantly below those of controls, and total fat intake was significantly elevated. Although litter size and pup weights did not differ significantly at birth, pups of obese mothers weighed significantly less than those of controls at weaning. Maternal obesity in lactation appears to influence both body weight regulation and lactational performance.     

Bone density changes in pregnant women treated with heparin: a prospective, longitudinal study.

Heparin plus aspirin significantly improves the live birth rate of women with primary antiphospholipid syndrome. Osteopenia is a major concern of long-term heparin therapy. We studied prospectively the bone mineral density (BMD) changes during pregnancy and the puerperium in 123 women with primary antiphospholipid syndrome treated with low-dose aspirin and subcutaneous low-dose heparin (46 women took unfractionated heparin and 77 took low-molecular-weight heparin). Lumbar spine, neck of femur and forearm BMD were measured, using dual energy X-ray absorptiometry, at 12 weeks gestation, immediately postpartum and 12 weeks postpartum. The mean heparin duration was 27 weeks (range 22-29). During pregnancy, BMD decreased by 3.7% (P < 0.001) at the lumbar spine and by 0.9% (P < 0.05) at the neck of femur with no significant change at the forearm. Lactation was associated with a significant decrease in the lumbar spine and neck of femur BMD. There was no significant difference in BMD changes between the two heparin preparations. No woman suffered a symptomatic fracture. Long-term heparin treatment during pregnancy is associated with a small but significant decrease in BMD at the lumbar spine and neck of femur. This decrease is similar to that previously reported to occur in untreated pregnancies.     

Body composition and dietary intake in relation to drug abuse in a cohort of HIV-positive persons

We examined the relationships between drug abuse, weight, body composition, and dietary intake in persons infected with HIV in a cross-sectional analysis of baseline data from a longitudinal study of nutritional status and HIV. Body composition was measured by bioelectrical impedance analysis. Dietary data were collected by 3-day food records or 24-hour recalls. We analyzed data from 39 current intravenous drug users (IVDU), 103 past intravenous drug users (past-IVDU), 239 users of nonintravenous drugs (users-NIVD), and 61 nonusers (reference category). In the men, there were no differences in weight, body mass index (BMI), or body composition among the drug-use groups. In the women, there was a trend to lower weight and BMI across the drug use categories: IVDU women had lower average weight (-13.7 kg; p = .006), BMI (-5.6 units; p = .003) and less fat mass than non-users (-9.8 kg; p = .0001). In women, drug users had higher weight-adjusted energy intakes than nonusers, whereas in the men both drug using groups, NIVD and IVDU, had higher energy intakes than nonusers. These data suggest that intravenous drug-abuse is associated with lower weight and fat mass in women with HIV infection despite adequate self-reported energy intake.     

Responses to laboratory psychosocial stress in postpartum women

OBJECTIVE: Lactation has been associated with attenuated hormonal responses to exercise stress in humans. This study was designed to determine the effect of lactation on hypothalamic-pituitary-adrenal axis, autonomic nervous system, and anxiety responses to psychological stress. METHOD: The Trier Social Stress Test was administered to 24 lactating women, 13 postpartum nonlactating women, and 14 healthy control women in the early follicular phase of the menstrual cycle. Lactating women were stressed at least 40 minutes after last feeding their infant. RESULTS: ACTH, cortisol, heart rate, diastolic blood pressure, systolic blood pressure, and subjective anxiety ratings were all significantly increased in response to the psychological stress (all p <.0001). There were no differences among the three groups in any of these responses to the stress. However, postpartum nonlactating women did have a persistently higher systolic blood pressure and lower cardiac vagal tone than the lactating women and control subjects. In addition, the typical negative correlation between cardiac vagal tone and heart rate was consistently higher in lactating women than nonlactating postpartum women and controls, which suggests stronger vagal control of heart rate in lactating women. In addition, there was no change in oxytocin or allopregnanolone in response to the stress, and baseline oxytocin and allopregnanolone levels did not differ among the three groups. CONCLUSIONS: These results indicate that physiological and subjective responses to social stress are not attenuated in lactating women tested at least one hour after feeding their infant. However, enhanced vagal control of cardiac reactivity was observed in lactating women. In addition, postpartum women who did not lactate showed evidence of increased sympathetic and decreased parasympathetic nervous system tone.     

Impact of food craving and calorie intake on body mass index (BMI) changes during an 18-month behavioral weight loss trial

The purpose of this study was to explore relations between food craving, caloric intake, and body mass index (BMI) changes over the course of an 18-month weight loss trial. Two-hundred two obese adults (mean BMI = 34.9 kg/m²; mean age = 51.30 years, 92.2% White; 57.8% female) who participated in a behavioral weight loss trial completed measures of food craving, caloric intake, and BMI at baseline, 6 and 18 months. From baseline to 6 months, higher initial food cravings were associated with more gradual and less steep reductions in BMI. Additionally, the relation between changes in food craving and BMI changes varied by levels of change in caloric intake, such that BMI change and change in food cravings were positively associated at low levels of change in caloric intake, but were unrelated at average and high levels of change in caloric intake. Similarly, from baseline to 6 months and from 6 to 18 months, the relation between changes in food craving and BMI changes also varied by initial levels of caloric intake. Explicit clinical targeting of food craving management may be beneficial for individuals beginning weight loss programs, especially for those who report higher levels of food craving at baseline. Baseline caloric intake and change in calorie intake over time may serve as moderators of the relation between food cravings and BMI.     

Influence of PROP taster status and maternal variables on energy intake and body weight of pre-adolescents

Genetic taste blindness to the bitterness of 6-n-propylthiouracil (PROP) may be a marker for increased energy intake and body weight. This hypothesis has not been tested in pre-adolescent children. This study determined if non-taster children would report higher energy intakes and maintain higher body weights than taster children. Maternal variables which are known to influence food intake and body weight during childhood were also considered including maternal weight, maternal restraint and disinhibition and child feeding practices. Sixty-five children with a mean age of 9.0 ± 0.2 years participated. They completed a 3-day diet recall for the estimation of daily energy and macronutrient intakes. BMI (mothers) and BMI%-for-age (children) were calculated from measured heights and weights. Non-taster children reported higher daily energy intakes than super-taster children (p ≤ 0.05), but no differences in macronutrient selection were observed. Also, children of disinhibited mothers reported higher daily energy intakes than children of mothers who were not disinhibited (p ≤ 0.05). However, these variables did not predict children's body weight. Rather, regression modeling (R² = 0.59; p ≤ 0.0001) revealed that restriction, concern for child weight and maternal BMI were positive predictors of children's BMI%-for-age and pressure to eat was a strong negative predictor (p-value range = 0.02–0.004). PROP status was not a predictor of body weight in these children. These results suggest that in pre-adolescent children, current energy intakes were negatively related to children's PROP status and positively related to maternal disinhibition. However, BMI%-for-age, a measure of long-term energy balance, was related to child feeding practices and maternal BMI.     

Variation in maternal strategies during lactation: The role of the biosocial context

Compared to other mammals, human milk is dilute which lowers the relative daily cost of lactation allowing women greater flexibility in the strategies they use to meet the energy demands of lactation. These strategies include increasing dietary intake, reducing energy expenditure, and drawing on energy stores. Women are affected by the biosocial context in which they live, including norms regarding the sexual division of labor and diet and activity patterns during lactation, as well as household‐level factors such as economic strategy and the availability of social support. This paper combines longitudinal data on dietary intake, energy expenditure, and body weight of 23 lactating Amazonian women living in a subsistence‐based economy with detailed ethnographic data and considers how adherence to the cultural norms and the availability of social support contributed to intra‐population variation in maternal energetic strategies. Dietary intake was found to vary more than energy expenditure. Adherence to dietary restrictions during the postpartum period of resguardo significantly reduced intra‐population variation in energy intake. Women with social support came closer to achieving energy balance during resguardo (t = 2.8; P = 0.01) and peak lactation (t = 2.7; P = 0.02) and lost less weight (t = 3.6; P = 0.002) than those without such support. Those with social support had higher energy (t = 2.1; P = 0.05) and carbohydrate (t = 2.1, P = 0.05) intakes during resguardo and spent significantly less time in subsistence work during peak (t = 2.6, P = 0.03) and late lactation(t = 2.4, P = 0.03). Case studies are used to place these finding in context. Am. J. Hum. Biol. 2009. © 2009 Wiley‐Liss, Inc.     

Biological and behavioral factors influence group differences in prolactin levels among breastfeeding Nepali women

This study of two natural fertility Nepali groups, the Tamang and Kami, identifies biological and behavioral factors associated with population differences in fertility. Previous research had established that Tamang experience longer interbirth intervals than Kami despite similarly intense nursing practices, and bear considerably higher energy expenditure due to workload. This cross-sectional study of 71 breastfeeding women includes prolactin determinations on three blood spot samples collected 5, 30, and 50 minutes following a timed nursing bout, and data on maternal age, BMI, menstrual status, previous birth interval, parity, infant age, nursing bout length, and durations of supplementation and postpartum amenorrhea. The findings show that Tamang breastfeeding mothers have higher average prolactin levels than Kami for as long as 22 months postpartum. Tamang mothers sustain average prolactin levels above those of nonpregnant, nonlactating women for nearly 2 years postpartum, whereas prolactin levels among Kami breastfeeding mothers are the same as this latter group after 1 year postpartum. Furthermore, the findings indicate that Tamang mothers have higher average prolactin levels regardless of maternal age, physical status (BMI, weight, or height), or infant age, and the rate of decline in prolactin from 5 to 50 minutes after suckling is significantly greater for Kami than Tamang. Since factors associated with prolactin levels differ by group, the findings also emphasize that populations vary not only in the strength of effects that proximate determinants have on fertility regulation, but also in the pathways by which they exert their effects (direct physiological versus indirect behavioral). Am. J. Hum. Biol. 10:191–210, 1998. © 1998 Wiley-Liss, Inc.     

Body mass index, eating attitudes, and symptoms of depression and anxiety in pregnancy and the postpartum period

OBJECTIVE: This report describes associations between body mass index (BMI; kg/m2), eating attitudes, and affective symptoms across pregnancy and the postpartum period in a sample of 64 women. METHODS: As part of a larger study, women were recruited during pregnancy and followed prospectively to 14 months postpartum. Measures included self-reported prepregnancy and 4-month postpartum BMI as well as pregnancy, 4-month, and 14-month postpartum eating attitudes (EAT), depressive symptoms (CES-D), and anxiety symptoms (STAI). RESULTS: During pregnancy, symptoms of depression or anxiety were not significantly correlated with concurrent eating attitudes or measures of BMI. However, at 14 months postpartum, measures of eating attitudes and both depression and anxiety symptoms were associated. Measures of BMI were associated with depressive and anxiety symptoms at both 4 and 14 months postpartum. Four-month eating attitudes and BMI predicted 14-month postpartum depressive symptoms, beyond pregnancy, and 4-month postpartum measures of affective symptoms. Results suggested that overweight women were at risk for elevated anxiety at 4 months and depressive symptoms at both 4 and 14 months postpartum. CONCLUSIONS: These results provide evidence for a significant, albeit moderate, relationship between BMI, eating attitudes, and symptoms of depression and anxiety in the postpartum period that are not present during pregnancy.     

Do combined elimination diet and prolonged breastfeeding of an atopic infant jeopardise maternal bone health?

BACKGROUND: Prolonged breastfeeding, and intervention in the maternal diet during breastfeeding, have been suggested as a means to treat atopic symptoms of infants. The impact of these actions on the mother's skeletal health has remained unclear. OBJECTIVE: The purpose of this study was to determine factors that are associated with bone mineral density (BMD) and serum lipid fatty acid profile in mothers of atopic infants. METHODS: BMD at the lumbar spine, right femoral neck and dominant distal radius of 24 mothers of atopic infants (study group) and 25 mothers of healthy infants (control group) were measured with dual energy X-ray absorptiometry postpartum after the resumption of menses. In addition, the fatty acid profile of their serum cholesteryl esters was determined. RESULTS: A systematic trend for 4-6% lower BMD was observed in the study group, but this difference was mainly attributable to a difference in body weight between the groups. In addition, the omega (omega)-3 fatty acid metabolite EPA showed a positive association with femoral neck BMD. Mothers of atopic infants had a significantly lower proportion of omega-6 fatty acid parent LA and a higher proportion of omega-6 fatty acid metabolite GLA than the control mothers. These differences were associated not only with dietary factors but also with the duration of postpartum amenorrhea and total lactation. CONCLUSIONS: Neither the breastfeeding nor the mother's short-term elimination diet per se seemed to be associated with low BMD in the mothers of atopic infants. Thus, if an elimination diet benefits the infant, it can be recommended for a limited period. However, it may be advisable to give special dietary counselling, especially to low body weight mothers, in order to ensure adequate nutrient intake and to minimize the possible risk of potential bone loss.     

Age,reproductive history,seasonality, and maternal body composition during pregnancy for nomadic Turkana of Kenya

To evaluate the potential differences in maternal nutritional investment in pregnancy, data collected from nomadic Ngisonyoka Turkana women during a July 1993–July 1994 field season were utilized. The roles maternal age, parity, duration of the previous nonpregnant interval, overlap between pregnancy and lactation on trimester changes in weight and summed skinfolds during pregnancy were examined. Because seasonality is an important aspect of the Turkana environment, the effects of seasonality were also assessed. First trimester weight gain is positively associated with overlap in pregnancy and lactation. Second trimester maternal weight gain is negatively influenced by higher parity and by overlap between lactation and early pregnancy. Third trimester weight gain is influenced only by seasonally induced morbidity. First trimester changes in maternal skinfolds are negatively influenced by older maternal age and parity, and positively influenced by a longer nonpregnant interval, and overlap between pregnancy and lactation. Second and third trimester skinfolds are significantly associated only with overlap between lactation and pregnancy (negatively in the second, positively in the third). Seasonality does not influence maternal skinfolds. Differences in age- and parity-related patterns of maternal nutritional investment in pregnancy are not supported by the data. The possibility that Turkana cultural beliefs may influence nutritional status during pregnancy is discussed. Am. J. Hum. Biol. 11:658–672, 1999. © 1999 Wiley-Liss, Inc.     

A 5-HT2C receptor promoter polymorphism (HTR2C - 759C/T) is associated with obesity in women, and with resistance to weight loss in heterozygotes.

The serotonin 5-HT(2C) receptor (HTR2C) helps regulate appetite and body weight. An HTR2C promoter polymorphism (-759C/T) has been associated with obesity and with weight gain in response to antipsychotic (neuroleptic) drugs. We studied this polymorphism in 120 obese women (BMI > or = 30) and 104 non-obese (BMI < or = 25) women. The C allele was commoner in the obese group (OR = 1.72 [95% CI, 1.13-2.64], P = 0.008). Ninety-five of the obese women participated in a randomized trial of psychological treatments for weight loss. Among these women, heterozygotes lost less weight during the trial than did homozygotes (6.8 vs. 9.7 kg; P = 0.047) and weighed more 6 months (90.1 vs. 83.6 kg; P = 0.006) and 12 months (91.8 vs. 84.6 kg; P = 0.009) later. Heterozygotes also had higher triglyceride levels than homozygotes. C/C subjects in the obesity trial did not differ from T/T subjects in terms of weight loss or triglycerides. In a separate RT-PCR study of 43 subjects, we found that HTR2C mRNA abundance in frontal cortex was unaffected by -759C/T status. Our data extend the evidence that HTR2C promoter variation may be a risk factor for obesity and, perhaps through heterosis, influences weight loss by obese women. Pharmacogenetic testing of HTR2C promoter variants may be valuable when evaluating anti-obesity drugs which act directly or indirectly on the receptor.     

Increased bone mineral density is associated with breastfeeding history in premenopausal Spanish women

Introduction

During lactation abundant calcium is lost from the mother as a result of the amount of breast milk produced. Lactation leads to transient fragility, with some women experiencing even fragility fractures, but nearly all of these women subsequently undergo a large increase in bone mineral density (BMD), confirming that the BMD must have declined during lactation but it increases after weaning. We have retrospectively examined the relationship between the duration of breastfeeding and bone properties in Spanish premenopausal healthy women, to identify the site-specific changes in BMD.

Material and methods

Four hundred and thirty-three premenopausal healthy women, 295 with a mean of 7.82 ±6.68 months of exclusive breastfeeding and 138 control women, were studied. We examined total, trabecular and cortical volumetric BMD (mg/mm³) at the distal radius using peripheral quantitative computed tomography. Areal BMD (g/cm²) was measured using dual energy X-ray absorptiometry at the femoral neck, lumbar spine, trochanter and Ward''s triangle. Phalangeal bone ultrasound was measured by amplitude-dependent speed of sound.

Results

Areal BMD analysis at L2–L4 revealed significant intergroup differences (p < 0.05). There were significant intergroup differences in the volumetric BMD in both total and cortical bone (p < 0.05). The observed BMD of breast-feeders was higher than the BMD in non-breast-feeding women. Additionally, the lactation subgroup analysis revealed significant differences in the areal BMD at trochanter and L2–L4 (p < 0.05) and in the cortical volumetric BMD (p < 0.05).

Conclusions

This study adds to the growing evidence that breastfeeding has no deleterious effects and may confer an additional advantage for BMD in premenopausal women.