ArticlePlus
Click on the links below to access all the ArticlePlus for this article.
Please note that ArticlePlus files may launch a viewer application outside of your web browser.
Preterm birth and reduced intrauterine growth have been associated with an increased risk for subsequent health problems such as the metabolic syndrome, diseases of the nervous system, mental disorders, and respiratory disease.1–6 There is also some evidence of a higher risk of some forms of cancer, infectious diseases, and altered reproductive function among these men and women.7–12 Most studies have evaluated those associations for selected diagnoses or conditions, although one study reported that lower birth weight was associated with all-cause mortality in early adult life among Danish men.13 Reasons for the poorer health status among those born preterm or small for gestational age (SGA) may include social, environmental, and biologic factors.1,3,14 It is therefore important to account for background characteristics such as socioeconomic condition when estimating the relation between preterm birth or reduced intrauterine growth and the risk of subsequent morbidity.
Swedish population-based registries offer an opportunity to study the relation of preterm birth and reduced intrauterine growth with the subsequent risk of hospitalization in a large sample of men and women. Through these registries, it is possible to obtain access to information on all causes of hospitalization and on individuals’ socioeconomic characteristics. The aims of the present study were to investigate whether the risk of hospitalization during adolescence and early adulthood differed between persons who were born preterm, or who were born SGA, as compared with those born at term and not SGA. We were interested in examining the overall risk of hospitalization, as well as hospitalization due to specific groups of diagnoses, and to determine whether associations were evident even after adjustments for childhood socioeconomic characteristics.
METHODS
The Swedish Medical Birth Register was established in 1973 and contains information on birth-related variables, as well as on the previous reproductive history of the mother.15 The Total Population Register includes information on births, deaths, and marital status, as well as migration and country of origin for Swedish residents born abroad.16 The Swedish Hospital Discharge Register covers all public inpatient care in Sweden since 1987.17 We also had access to the Causes of Death Register, which records information on all deceased persons registered in the country at the time of death,18 and the Multi-Generation Register,19 which makes it possible to identify the fathers of the children registered in the Medical Birth Register and the Total Population Register. Information on the educational level of the study population’s parents was retrieved from the 1970 Population and Housing Census.20
Our study population comprised all men and women born in 1973, 1974, and 1975 (based on the Birth and Population Registers), and who were alive and still living in Sweden at 13 years of age (n = 308,787). Information available in the other registries was retrieved by use of the infant’s or mother’s unique personal identification number. Men and women with missing values on birth weight or gestational length were excluded (n = 2190), as were those with extremely high birth weights in relation to their length of gestation (n = 293). We also excluded men and women reported to have been born before 29 weeks weighing more than 2000 g; those born at 29 or 30 weeks weighing more than 2500 g; those born at 31 or 32 weeks weighing more than 3000 g; and those born at 33 or 34 weeks weighing more than 3500 g. In addition, 2164 men and women were excluded because it was not possible to identify 1 or both parents in the registries. The final cohort therefore consisted of 304,275 (155,994 men and 148,281 women) for whom we could calculate their risk of being hospitalized from the beginning of 1987 to the end of 1996 (ie, between 12 and 23 years of age). During the study period (ie, 1987–1996), 1.3% of the men and women emigrated and 0.4% died. There were no differences in median follow-up time between those born preterm or SGA compared with those born at term and not SGA (data not shown).
We defined preterm birth as less than 37 completed weeks of gestation, and SGA as a birth weight less than 2 standard deviations below the mean weight for gestational length according to the Swedish standard.21 We then categorized men and women into 3 mutually exclusive groups: preterm and not SGA, SGA born at term, and SGA and preterm. We will refer to these groups as “preterm,” “SGA,” and “(both) preterm and SGA.” In some analyses, the preterm group was subdivided into very preterm (<32 weeks) and moderately preterm (32–36 weeks).
We included the following parental socioeconomic characteristics: mothers’ and fathers’ educational levels in the year of 1970; parents’ country of origin; and mothers’ marital status, parity, and age at the time of giving birth (ie, in 1973–1975) (Table 1). The educational levels were coded according to the Swedish educational system: elementary school (9 or 10 years of education), high school (11–13 years), and graduate and postgraduate education (14 years or more). The parents’ country of origin was coded to indicate if 1 or both parents had been born outside the Nordic countries. The marital status of the mothers were coded as married, unmarried, and divorced or widowed. The mother’s parity at the time of giving birth was split into 2 categories: no previous children and 1 or more previous children. Mothers were divided into 4 age categories: ≤19, 20–26, 27–33, and ≥34 years. In addition, the sex and year of birth of the men and women studied (ie, 1973, 1974, and 1975) and “twin birth” (yes/no) were included as background variables. Parents’ education level was missing for 8% of fathers and 12% of mothers. Furthermore, the parents with missing data tended to be younger and more likely to have been born outside the Nordic countries.22 Therefore, a “missing values” category was added for the 2 education variables. Missing values for other variables (<2% on each variable) were assigned to the largest category for each variable.
;)
TABLE 1: Background Characteristics in Relation to the Overall Risk of Hospitalization in Adolescence and Early Adulthood Among 304,275 Swedish Men and Women
Data on hospitalizations were collected from 1987 until 1996 by using the Hospital Discharge Register. The diagnoses are based on the Swedish version of the World Health Organization’s International Classification of Diseases (ICD); and between 1987 and 1996 the 9th revision (ICD-9) was used.23 The diagnoses listed in the ICD-9 are categorized into 17 chapters, and each chapter includes a range of more specific diagnoses (eTable 1, available with the online version of this article). The most commonly presented diagnoses on the more specific level are the diagnoses on the “three-digit level.” We did not include in the analysis hospitalizations according to 2 of the ICD chapters: “complications of pregnancy, childbirth, and puerperium” and “certain conditions originating in the perinatal period.” For each ICD chapter and main diagnosis, hospitalization during adolescence and early adulthood was treated as a dichotomy, ie, either “hospitalized 1 or more times during the study period” or “not hospitalized during the study period.” Information on the main diagnosis for hospitalization was missing for 2.7% of the study population; missing values for the main diagnosis were treated as “not hospitalized” in the analyses. This resulted in 3023 (1.0%) of men and women being classified as not hospitalized according to any of the ICD chapters. Excluding these men and women from the analyses did not change the results (data not shown).
This study was approved by the Human Research Ethics Committee, Faculty of Health Sciences, Linköping University.
Statistical Analyses
We used multiple logistic regression analysis to evaluate whether men and women born preterm, SGA, and both preterm and SGA, were more likely to be hospitalized in adolescence and early adulthood, as compared with men and women who were born at term and not SGA. Odds ratios and 95% confidence intervals were adjusted for the background variables presented in Table 1. The dependent variables were hospitalizations (yes or no) for illnesses in the 15 studied ICD chapter categories.
To evaluate the associations in more detail, we also used hospitalizations due to the 3 most common main diagnoses for the men and women on the three-digit level in each ICD chapter as dependent variables. This screening was performed by use of multiple logistic regression analysis. Acknowledging the large number of comparisons, we set the significance level to P ≤ 0.01. A selected output of the screening is presented in Tables 2–4. All diagnoses included in the screening are presented in eTable 1.
TABLE 2: Hospitalization According to Selected 3-Digit Level Diagnoses Among Swedish Men and Women Born Preterm, by ICD Chapter
TABLE 3: Hospitalization According to Selected 3-Digit Level Diagnoses Among Swedish Men and Women Born SGA, by ICD Chapter
TABLE 4: Hospitalization According to Selected 3-Digit Level Diagnoses Among Swedish Men and Women Born Preterm and SGA, by ICD Chapter
RESULTS
Of the Swedish men and women born in 1973–1975, 30% (91,247) were hospitalized at least once between 1987 and 1996 for diagnoses in the 15 ICD chapters studied. The most common causes of hospitalization during adolescence and early adulthood were diagnoses related to “injury, poisoning, and other external causes,” and “symptoms, signs, and ill-defined conditions” (eTable 1). All childhood socioeconomic characteristics included in the present study except for the parents’ country of origin appeared to be related to the overall risk of hospitalization; lower socioeconomic status tended to be associated with a higher risk for hospitalization (Table 1). Also, women were somewhat more likely to have been hospitalized than men, and both men and women born in 1973 were more likely to have been hospitalized than those born in later years. Twins were of lower risk of being hospitalized in adolescence and early adulthood.
Preterm Birth
The 12,248 (4.0%) men and women who were born preterm (and not SGA) had an overall 6% increased risk of hospitalization after adjusting for the background characteristics presented in Table 1, compared with those born at term and not SGA (Fig. 1 and Table 2). More specifically, being born preterm was associated with hospitalizations for “endocrine, nutritional, and metabolic diseases,” “mental disorders,” “diseases of the nervous system,” “congenital anomalies,” and “symptoms, signs, and ill-defined conditions.” The sex-specific analyses are presented in online appendix eTable 3.
FIGURE 1.:
Hospitalization in adolescence and early adulthood among Swedish men and women born preterm (only), by ICD chapter. Odds ratios (circles) and 95% confidence intervals (horizontal bar), adjusted for the background characteristics presented in
Table 1. More precise risk estimates are provided in eTable 2.
We screened the most common three-digit level diagnoses listed in each ICD chapter (Table 2). Preterm birth was most strongly related to “diabetes mellitus” and “other disorders of pancreatic internal secretion” (within the “endocrine, nutritional, and metabolic diseases” category). “Strabismus and other disorders of binocular eye” and “epilepsy” were most prominent in the category of “diseases of the nervous system,” while “congenital anomalies of genital organs” contributed strongly to the association with “congenital anomalies.” Among those hospitalized due to “congenital anomalies of genital organs,” the most commonly occurring subgroup was the four-digit level diagnosis “undescended testicle” among the men and “anomalies of cervix, vagina, and external female genitalia” among the women. The most common subgroup among men and women hospitalized due to “general symptoms” (as part of “symptoms, signs and ill-defined conditions”) was “syncope and collapse.” Men and women born preterm were also at somewhat higher risk for “diseases of the skin and subcutaneous tissue,” compared with those born at term (Fig. 1), but no additional associations emerged in the screening (Table 2). Screening suggested that those born preterm may be of lower risk for hospitalizations due to “other disorders of breast” (with “hypertrophy of breast” as the most potential subgroup).
When preterm births (not SGA) were categorized into those born very preterm and moderately preterm, the overall increased risk was 1.18 (95% confidence interval = 1.03–1.36) for very preterm and 1.05 (1.01–1.09) for moderately preterm. The differences between the 2 preterm groups were most pronounced for “diseases of the nervous system,” “diseases of the skin and subcutaneous tissue,” and “congenital anomalies” (data not shown).
Small for Gestational Age
A total of 14,113 (4.6%) of the men and women were born SGA (and term). Their overall risk of hospitalization was increased by 16%, compared with those born at term and not SGA (Fig. 2 and eTable 2).
FIGURE 2.:
Hospitalization in adolescence and early adulthood among Swedish men and women born small for gestational age (only), by ICD chapter. Odds ratios (circles) and 95% confidence intervals (horizontal bar), adjusted for the background characteristics presented in
Table 1. More precise risk estimates are provided in eTable 2.
Similar to those born preterm, those born SGA had increased risks for “mental disorders,” “diseases of the nervous system,” “congenital anomalies,” and “symptoms, signs, and ill-defined conditions.” Screening of the three-digit level diagnoses showed associations with “nondependent use of drugs,” “adjustment reaction,” and “disturbance of emotions specific to childhood and adolescence” (Table 3) within the general category of “mental disorders.” The association of SGA with “injury, poisoning, and other external causes,” was due largely to “poisoning by analgesics, antipyretics, and antirheumatics” (Fig. 2 and Table 3). Being born SGA was related to “diseases of the genitourinary system” (Fig. 2), and this association was evident even after stratifying women into those who had given birth and those who did not give birth, and after excluding men and women with congenital anomalies of genital organs (data not shown). Among the men, the strongest association was found for “other disorders of the male genital organs” (with “torsion of testis” as the largest four-digit-level group) (Table 3).
Although there appeared to be no association between SGA and “endocrine, nutritional, and metabolic diseases” on the ICD chapter level, the screening suggested possible associations for both men and women with “other endocrine disorders” (with “short stature, not elsewhere classified” as the most common subgroup) (Table 3).
Both Preterm Birth and SGA
The 1290 (0.4%) men and women who were born both preterm and SGA had an increased overall risk of 42% of being hospitalized, higher than for those born either preterm or SGA (Fig. 3 and eTable 2). As seen earlier for men and women who were born preterm or SGA, those born both preterm and SGA had increased risks for “mental disorders,” “diseases of the nervous system,” and “congenital anomalies.” The three-digit level diagnoses with the strongest associations in these categories were “drug dependence,” “nonsuppurative otitis media and Eustachian tube disorders,” and “congenital anomalies of genital organs” (Table 4).
FIGURE 3.:
Hospitalization in adolescence and early adulthood among Swedish men and women born both preterm and small for gestational age, by ICD chapter. Odds ratios (circles) and 95% confidence intervals (horizontal bar), adjusted for the background characteristics presented in
Table 1. More precise risk estimates are provided in eTable 2.
DISCUSSION
Men and women who were born SGA or preterm had higher risks of being hospitalized during adolescence and early adulthood, compared with those born appropriate for gestational age and at term. Risks were highest for those who were born both SGA and preterm. Reasons for poorer health among those born SGA or preterm may include social, environmental, and biologic factors.1,3,14 The associations in our data persisted even after adjustment for childhood socioeconomic factors. There are speculations that adaptations made by the undernourished fetus or young infant may have long-term effects on health,1 which could be involved in explaining the differences in hospitalization risk between preterm and SGA. We previously showed that women who were born SGA had parents of lower socioeconomic status at the time of giving birth compared with women born preterm, but also that women born SGA had somewhat lower educational levels at the age of 25 even after adjustments were made for childhood socioeconomic characteristics.12 Thus, even though we were able to adjust for several childhood socioeconomic characteristics, there may still be residual confounding by socioeconomic position, as discussed by Blakely et al.24
As in other studies, we found neurodevelopment sequelae among men and women born preterm or SGA that persisted into young adulthood.2,3,25 The risk was highest among those born both preterm and SGA. Preterm birth and SGA were both related to increased risk of mental disorders, which is in line with previous research.2–4,26,27 Those born SGA were more prone to be hospitalized for to nondependent use of drugs, while those born both preterm and SGA were more likely to be hospitalized for drug dependence. Those born SGA also were at risk for “injury, poisoning, and other external causes,” (especially “poisoning by analgesics, antipyretics, and antirheumatics”), in keeping with 2 Nordic studies.13,28 However, a recent review showed that young adults born with very low birth weights reported less risk-taking behavior, including drug and alcohol use, compared with controls.3 This discrepancy might be due to differences between SGA and very-low-birth-weight children. Differences between the Nordic countries and the United States and Canada (eg, in terms of social and cultural factors) might also contribute to the discrepancy.
Men and women born SGA or preterm were at higher risk of hospitalization for “symptoms, signs, and ill-defined conditions.” Diagnoses related to this category of diagnoses have not previously been reported, although hospitalizations for these reasons are among the most common causes of hospitalization during adolescence and early adulthood, at least in Sweden. Men and women who were born SGA had more “ill-defined intestinal infections.” Low birth weight, particularly in combination with preterm birth, has previously been associated with infectious disease in childhood.9 There is also some evidence of preterm birth leading to hospitalization for appendicitis.29 In the present study, men and women born SGA had a decreased risk for hospitalization due to acute appendicitis. Although it is only conjecture, those born SGA or preterm might be more prone to seek medical advice for less severe conditions, as previously hypothesized by Källén et al.29 This could, in turn, be explained by the observation that these men and women are more anxious, according to both themselves and their parents.3
SGA was also associated with subsequent hospitalization for genitourinary diseases. There is some evidence of a connection between reduced intrauterine growth and altered reproductive function,10,11 although most human studies are based on highly selected hospital populations or on relatively small numbers of people. Men and women who were born SGA or preterm had higher risk of congenital anomalies of genital organs, in keeping with previous studies.10 Studies have suggested that women born SGA have a higher probability of giving birth before the age of 27, while women with birth defects had a lower probability of childbearing.12,30 Thus, we performed additional analyses on the association of SGA and genitourinary diseases, accounting for whether the women had given birth during the study period and whether the men and women had congenital anomalies of genital organs. These additional analyses did not substantially change the relationship. The higher risk for genitourinary diseases among men and women born SGA may be explained by an earlier sexual debut or higher levels of sexual activity, which, in turn, could be associated with socioeconomic differences between SGA and appropriate for gestational age.12
Previous studies have shown that low birth weight is related to an increased risk of metabolic syndrome in adult life. There is also some evidence of a higher risk of childhood onset of type-1 diabetes among those born SGA or preterm.1,31,32 Low birth weight predicts short stature in adulthood among men and women.33,34 We found that those born SGA seemed to be at higher risk for hospitalization due to short stature. We also found modest evidence for respiratory diseases and diseases of the skin among those born SGA or preterm. Respiratory disease has been reported to be more common among SGA and preterm babies.3,5,6 We found no evidence of association between preterm birth or SGA and subsequent risk of “neoplasm,” consistent with a previous Swedish study.35
One of the major strengths of this study is that the results are based on a large population-based cohort with prospectively collected register data. Swedish population-based registries offer an opportunity to link birth data to all causes of hospitalization later in life. Thus, we were able to examine broadly the effects of preterm birth and SGA on hospitalizations during adolescence and early adulthood. Although the quality of Swedish registries is generally good,15–20 the Hospital Discharge Register includes errors that may have affected the results.17,36 In validation studies, the errors on the ICD chapter level were estimated to be 6% in 1986 and 4% in 1990; the highest relative frequency of errors was for diagnoses related to internal medicine, and the lowest for gynecologic diagnoses.36 In addition, the average number of days of hospitalization has decreased from 20.8 in 1987 to 6.4 in 2000.37 Thus, the likelihood of hospitalization due to certain diagnoses may have changed over time. There has been considerable improvement in the medical treatment of children born preterm and SGA from the 1970s to today, resulting in a much higher survival rate. The consequences of the higher survival rate include a higher relative number of injured children or children with chronic conditions, compared with the 1970s. Therefore, the relationships found in this study may not be evident in more recent cohorts. However, several of the associations found in the present study have been reported in other studies as well.
A consequence of screening the most frequently occurring three-digit level diagnoses is an increased risk of false positive findings. We used more stringent criterion (P ≤ 0.01) in screening, and also focused the discussion on the more general or consistent relationships. It is also important to keep in mind that we studied hospitalizations, not morbidity. Hospitalizations cover only the more serious conditions, and the likelihood of being hospitalized may be influenced by social and behavioral factors. We controlled for childhood socioeconomic conditions available in the registries, but this may not have removed all confounding. It would have been of value to consider the effect of factors for which no data are present in the registries, such as behavioral factors, particularly regarding the connection between SGA and hospitalizations due to drug use.
This study, contributes to the growing body of evidence that SGA and preterm birth are linked to health problems in later life. Men and women who were born SGA seemed to be more at risk than those born preterm. In addition to increased risks for previously known adverse health outcomes, such as neurodevelopment sequelae, mental disorders, and congenital anomalies, persons born SGA or preterm were more likely to be hospitalized for “symptoms, signs, and ill-defined conditions,” while SGA was in addition association with genitourinary diseases, drug use, and “injury, poisoning, and other external causes.”
ACKNOWLEDGMENTS
We thank the Swedish National Board of Health and Welfare and Statistics Sweden for help and access to the registries.
REFERENCES
1. Barker DJP.
Mothers, Babies and Health in Later Life. 2nd ed. Edinburgh, Scotland: Churchill Livingstone; 1998.
2. Yanney M, Marlow N. Paediatric consequences of fetal growth restriction.
Semin Fetal Neonatal Med. 2004;9:411–418.
3. Hack M. Young adult outcomes of very-low-birth-weight children.
Semin Fetal Neonatal Med. 2006;11:127–137.
4. Eaton WW, Mortensen PB, Thomsen PH, et al. Obstetric complications and risk for severe psychopathology in childhood.
J Autism Dev Disord. 2001;31:279–285.
5. Mai XM, Gäddlin PO, Nilsson L, et al. Asthma, lung function and allergy in 12-year-old children with very low birth weight: a prospective study.
Pediatr Allergy Immunol. 2003;14:184–192.
6. Bernsen RM, de Jongste JC, Koes BW, et al. Perinatal characteristics and obstetric complications as risk factors for asthma, allergy and eczema at the age of 6 years.
Clin Exp Allergy. 2005;35:1135–1140.
7. Akre O, Ekbom A, Hsieh CC, et al. Testicular nonseminoma and seminoma in relation to perinatal characteristics.
J Natl Cancer Inst. 1996;88:883–889.
8. Mellemkjaer L, Olsen ML, Sorensen HT, et al. Birth weight and risk of early-onset breast cancer (Denmark).
Cancer Causes Control. 2003;14:61–64.
9. Yuan W, Basso O, Sorensen HT, et al. Indicators of fetal growth and infectious disease in childhood—a birth cohort with hospitalization as outcome.
Eur J Epidemiol. 2001;17:829–834.
10. Main KM, Jensen RB, Asklund C, et al. Low birth weight and male reproductive function.
Horm Res. 2006;65(suppl 3):116–122.
11. Ibanez L, de Zegher F. Puberty after prenatal growth restraint.
Horm Res. 2006;65(suppl 3):112–115.
12. Ekholm K, Carstensen J, Finnström O, et al. The probability of giving birth among women who were born preterm or with impaired fetal growth: a Swedish population-based registry study.
Am J Epidemiol. 2005;161:725–733.
13. Andersen AM, Osler M. Birth dimensions, parental mortality, and mortality in early adult age: a cohort study of Danish men born in 1953.
Int J Epidemiol. 2004;33:92–99.
14. Kramer MS, Joseph KS. Enigma of fetal/infant-origins hypothesis.
Lancet. 1996;348:1254–1255.
15. Centre for Epidemiology, National Board of Health and Welfare.
The Swedish Medical Birth Register; A Summary of Content and Quality. Stockholm, Sweden: National Board of Health and Welfare; 2003 (Article no. 2003-112-3). Available at:
http://www.sos.se/fulltext/112/2003-112-3/2003-112-3.pdf. Accessed March 17, 2006.
16. Statistics Sweden.
A New Total Population Register System. More Possibilities and Better Quality. Örebro, Sweden: Statistics Sweden; 2002 (Serial no. 2002:2).
17. Centre for Epidemiology, National Board of Health and Welfare.
In-Patient Diseases in Sweden 1987–2001. Stockholm, Sweden: National Board of Health and Welfare; 2003 (Article no. 2003-42-8). Available at:
http://www.sos.se/fulltext/42/2003-42-8/2003-42-8.pdf. Accessed March 17, 2006.
18. Centre for Epidemiology, National Board of Health and Welfare.
Causes of Death 2001. Stockholm, Sweden: National Board of Health and Welfare; 2003. Available at:
http://www.sos.se/FULLTEXT/42/2003-42-5/2003-42-5.pdf. Accessed March 17, 2006.
19. Statistics Sweden.
Multi-Generation Register 2002. A Description of Contents and Quality.Örebro, Sweden: Statistics Sweden; 2003 (Serial no. 2003:5).
20. Statistics Sweden.
Population and Housing Census 1970 (SOS). Part 12. Report on the Planning and Processing of the Population and Housing Census 1970. Stockholm, Sweden: National Central Bureau of Statistics; 1974.
21. Marsal K, Persson PH, Larsen T, et al. Intrauterine growth curves based on ultrasonically estimated foetal weights.
Acta Paediatr. 1996;85:843–848.
22. Statistics Sweden.
Population and Housing Census 1970. Part 13. Economic Activity and Education. Definitions, Comparability, Development, etc. Stockholm, Sweden: National Central Bureau of Statistics, 1975; 1975.
23. Centre for Epidemiology, National Board of Health and Welfare.
The Swedish Version of 9th Revision of WHO’s International Classification of Diseases. Stockholm, Sweden: National Board of Health and Welfare; 1987. Available at:
http://www.sos.se/epc/klassifi/FILER/klass87.pdf. Accessed March 17, 2006.
24. Blakely T, Hunt D, Woodward A. Confounding by socioeconomic position remains after adjusting for neighbourhood deprivation: an example using smoking and mortality.
J Epidemiol Community Health. 2004;58:1030–1031.
25. Ericson A, Källén B. Very low birthweight boys at the age of 19.
Arch Dis Child Fetal Neonatal Ed. 1998;78:F171–F174.
26. Cnattingius S, Hultman CM, Dahl M, et al. Very preterm birth, birth trauma, and the risk of anorexia nervosa among girls.
Arch Gen Psychiatry. 1999;56:634–638.
27. Indredavik MS, Vik T, Heyerdahl S, et al. Psychiatric symptoms and disorders in adolescents with low birth weight.
Arch Dis Child Fetal Neonatal Ed. 2004;89:F445–F450.
28. Mittendorfer-Rutz E, Rasmussen F, Wasserman D. Restricted fetal growth and adverse maternal psychosocial and socioeconomic conditions as risk factors for suicidal behaviour of offspring: a cohort study.
Lancet. 2004;364:1135–1140.
29. Källén B, Finnström O, Nygren KG, et al. In vitro fertilization in Sweden: child morbidity including cancer risk.
Fertil Steril. 2005;84:605–610.
30. Skjaerven R, Wilcox AJ, Lie RT. A population-based study of survival and childbearing among female subjects with birth defects and the risk of recurrence in their children.
N Engl J Med. 1999;340:1057–1062.
31. Stene LC, Magnus P, Lie RT, et al. Birth weight and childhood onset type 1 diabetes: population based cohort study.
BMJ. 2001;322:889–892.
32. Svensson J, Carstensen B, Mortensen HB, et al. Early childhood risk factors associated with type 1 diabetes—is gender important?
Eur J Epidemiol. 2005;20:429–434.
33. Lundgren EM, Cnattingius S, Jonsson B, et al. Prediction of adult height and risk of overweight in females born small-for-gestational-age.
Paediatr Perinat Epidemiol. 2003;17:156–163.
34. Tuvemo T, Cnattingius S, Jonsson B. Prediction of male adult stature using anthropometric data at birth: a nationwide population-based study.
Pediatr Res. 1999;46:491–495.
35. Mogren I, Damber L, Tavelin B, et al. Characteristics of pregnancy and birth and malignancy in the offspring (Sweden).
Cancer Causes Control. 1999;10:85–94.
36. Centre for Epidemiology, National Board of Health and Welfare.
Patientregistret: Utskrivningar från slutenvård 1964–2004, kvalitet och innehåll. (The Swedish Hospital Discharge Register: Discharges from in-patient care1964-2004, quality and contents) (In Swedish). Stockholm, Sweden: National Board of Health and Welfare; 2006. Available at:
http://www.socialstyrelsen.se/NR/rdonlyres/BCCD170B-E998-411B-8F6A-40A2E6A3890D/0/Kvalitetochinnehåll19642004.pdf. Accessed March 17, 2006.
37. Centre for Epidemiology, National Board of Health and Welfare.
Yearbook of Health and Medical Care 2002. Stockholm, Sweden: National Board of Health and Welfare; 2003 (Article no. 2002-46-01). Available at:
http://www.socialstyrelsen.se/NR/rdonlyres/EB300B25-B8CB-4CE3-8F51-CCEAA09E96D9/1285/2002462.pdf. Accessed November 16, 2006.
